A176 ASSOCIATIONS OF ANTIBIOTICS, HORMONAL THERAPIES, ORAL CONTRACEPTIVES, AND LONG-TERM NSAIDS WITH INFLAMMATORY BOWEL DISEASE: RESULTS FROM THE PROSPECTIVE URBAN RURAL EPIDEMIOLOGY (PURE) STUDY

Background

The pathogenesis of inflammatory bowel disease (IBD) which includes Crohn’s disease (CD) and ulcerative colitis (UC), is believed to involve activation of the intestinal immune system in response to the gut microbiome among genetically susceptible hosts. IBD has been historically regarded as a disease of developed nations, though in the past two decades there has been a reported shift in the epidemiological pattern of disease. High-income nations with known high prevalence of disease are seeing a stabilization of incident cases, while a rapid rise of incident IBD is being observed in developing nations. This suggests that environmental exposures may play a role in mediating the risk of developing IBD. The potential environmental determinants of IBD across various regions is vast, though medications have been increasingly recognized as one broad category of risk factors.

Purpose

Several medications have been considered to contribute to the etiology of IBD. This study assessed the association between medication use and risk of developing IBD using the Prospective Urban Rural Epidemiology (PURE) cohort.

Method

This was a prospective cohort study of 133,137 individuals between the ages of 20-80 from 24 countries. Country-specific validated questionnaires documented baseline and follow-up medication use. Participants were followed prospectively at least every 3 years. The main outcome was development of IBD, including CD and UC. Short-term (baseline but not follow-up use) and long-term use (baseline and subsequent follow-up use) was evaluated. Results are presented as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Result(s)

During the median follow-up of 11.0 years [interquartile range (IQR) 9.2-12.2], we recorded 571 incident cases of IBD (143 CD and 428 UC). Higher risk of incident IBD was associated with baseline antibiotic use [aOR: 2.81 (95% CI: 1.67-4.73), p=0.0001] and hormonal medication use [aOR: 4.43 (95% CI: 1.78-11.01), p=0.001]. Among females, previous or current oral contraceptive use was also associated with IBD development [aOR: 2.17 (95% CI: 1.70-2.77), p=5.02E-10]. NSAID users were also observed to have increased risk of IBD [aOR: 1.80 (95% CI: 1.23-2.64), p=0.002], which was driven by long-term users [aOR: 5.58 (95% CI: 2.26-13.80), p<0.001]. All significant results were consistent in direction for CD and UC with low heterogeneity.

Conclusion(s)

Antibiotics, hormonal medications, oral contraceptives, and long-term NSAID use were associated with increased odds of incident IBD after adjustment for covariates.

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Salim Yusuf is supported by the Heart & Stroke Foundation/Marion W. Burke Chair in Cardiovascular Disease. The PURE Study is an investigator-initiated study funded by the Population Health Research Institute, the Canadian Institutes of Health Research (CIHR), Heart and Stroke Foundation of Ontario, support from CIHR’s Strategy for Patient Oriented Research (SPOR) through the Ontario SPOR Support Unit, as well as the Ontario Ministry of Health and Long-Term Care and through unrestricted grants from several pharmaceutical companies, with major contributions from AstraZeneca (Canada), Sanofi-Aventis (France and Canada), Boehringer Ingelheim (Germany and Canada), Servier, and GlaxoSmithkline, and additional contributions from Novartis and King Pharma and from various national or local organisations in participating countries; these include: Argentina: Fundacion ECLA; Bangladesh: Independent University, Bangladesh and Mitra and Associates; Brazil: Unilever Health Institute, Brazil; Canada: Public Health Agency of Canada and Champlain Cardiovascular Disease Prevention Network; Chile: Universidad de la Frontera; China: National Center for Cardiovascular Diseases; Colombia: Colciencias, grant number 6566-04-18062; India: Indian Council of Medical Research; Malaysia: Ministry of Science, Technology and Innovation of Malaysia, grant numbers 100 -IRDC/BIOTEK 16/6/21 (13/2007) and 07-05-IFN-BPH 010, Ministry of Higher Education of Malaysia grant number 600 -RMI/LRGS/5/3 (2/2011), Universiti Teknologi MARA, Universiti Kebangsaan Malaysia (UKM-Hejim-Komuniti-15-2010); occupied Palestinian territory: the UN Relief and Works Agency for Palestine Refugees in the Near East, occupied Palestinian territory; International Development Research Centre, Canada; Philippines: Philippine Council for Health Research & Development; Poland: Polish Ministry of Science and Higher Education grant number 290/W-PURE/2008/0, Wroclaw Medical University; Saudi Arabia: the Deanship of Scientific Research at King Saud University, Riyadh, Saudi Arabia (research group number RG -1436-013); South Africa: the North-West University, SANPAD (SA and Netherlands Programme for Alternative Development), National Research Foundation, Medical Research Council of SA, The SA Sugar Association (SASA), Faculty of Community and Health Sciences (UWC); Sweden: grants from the Swedish state under the Agreement concerning research and education of doctors; the Swedish Heart and Lung Foundation; the Swedish Research Council; the Swedish Council for Health, Working Life and Welfare, King Gustaf V’s and Queen Victoria Freemasons Foundation, AFA Insurance, Swedish Council for Working Life and Social Research, Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, grant from the Swedish State under the Läkar Utbildnings Avtalet agreement, and grant from the Västra Götaland Region; Turkey: Metabolic Syndrome Society, AstraZeneca, Turkey, Sanofi Aventis, Turkey; United Arab Emirates (UAE): Sheikh Hamdan Bin Rashid Al Maktoum Award For Medical Sciences and Dubai Health Authority, Dubai UAE.

Disclosure of Interest

C. Pray: None Declared, N. Narula Grant / Research support from: Neeraj Narula holds a McMaster University Department of Medicine Internal Career Award. Neeraj Narula has received honoraria from Janssen, Abbvie, Takeda, Pfizer, Merck, and Ferring, E. C. Wong: None Declared, J. K. Marshall Grant / Research support from: John K. Marshall has received honoraria from Janssen, AbbVie, Allergan, Bristol-Meyer-Squibb, Ferring, Janssen, Lilly, Lupin, Merck, Pfizer, Pharmascience, Roche, Shire, Takeda and Teva., S. Rangarajan: None Declared, S. Islam: None Declared, A. Bahonar: None Declared, K. F. Alhabib: None Declared, A. Kontsevaya: None Declared, F. Ariffin: None Declared, H. U. Co: None Declared, W. Al Sharief: None Declared, A. Szuba: None Declared, A. Wielgosz: None Declared, M. L. Diaz: None Declared, R. Yusuf: None Declared, L. Kruger: None Declared, B. Soman: None Declared, Y. Li: None Declared, C. Wang: None Declared, L. Yin: None Declared, M. Erkin: None Declared, F. Lanas: None Declared, K. Davletov: None Declared, A. Rosengren: None Declared, P. Lopez-Jaramillo: None Declared, R. Khatib: None Declared, A. Oguz: None Declared, R. Iqbal: None Declared, K. Yeates: None Declared, Á. Avezum: None Declared, W. Reinisch Consultant of: Speaker for Abbott Laboratories, Abbvie, Aesca, Aptalis, Astellas, Centocor, Celltrion, Danone Austria, Elan, Falk Pharma GmbH, Ferring, Immundiagnostik, Mitsubishi Tanabe Pharma Corporation, MSD, Otsuka, PDL, Pharmacosmos, PLS Education, Schering-Plough, Shire, Takeda, Therakos, Vifor, Yakult, Consultant for Abbott Laboratories, Abbvie, Aesca, Algernon, Amgen, AM Pharma, AMT, AOP Orphan, Arena Pharmaceuticals, Astellas, Astra Zeneca, Avaxia, Roland Berger GmBH, Bioclinica, Biogen IDEC, Boehringer-Ingelheim, Bristol-Myers Squibb, Cellerix, Chemocentryx, Celgene, Centocor, Celltrion, Covance, Danone Austria, DSM, Elan, Eli Lilly, Ernest & Young, Falk Pharma GmbH, Ferring, Galapagos, Genentech, Gilead, Grünenthal, ICON, Index Pharma, Inova, Janssen, Johnson & Johnson, Kyowa Hakko Kirin Pharma, Lipid Therapeutics, LivaNova, Mallinckrodt, Medahead, MedImmune, Millenium, Mitsubishi Tanabe Pharma Corporation, MSD, Nash Pharmaceuticals, Nestle, Nippon Kayaku, Novartis, Ocera, Omass, Otsuka, Parexel, PDL, Periconsulting, Pharmacosmos, Philip Morris Institute, Pfizer, Procter & Gamble, Prometheus, Protagonist, Provention, Robarts Clinical Trial, Sandoz, Schering-Plough, Second Genome, Seres Therapeutics, Setpointmedical, Sigmoid, Sublimity, Takeda, Therakos, Theravance, Tigenix, UCB, Vifor, Zealand, Zyngenia, and 4SC, Advisory board member for Abbott Laboratories, Abbvie, Aesca, Amgen, AM Pharma, Astellas, Astra Zeneca, Avaxia, Biogen IDEC, Boehringer-Ingelheim, Bristol-Myers Squibb, Cellerix, Chemocentryx, Celgene, Centocor, Celltrion, Danone Austria, DSM, Elan, Ferring, Galapagos, Genentech, Grünenthal, Inova, Janssen, Johnson & Johnson, Kyowa Hakko Kirin Pharma, Lipid Therapeutics, MedImmune, Millenium, Mitsubishi Tanabe Pharma Corporation, MSD, Nestle, Novartis, Ocera, Otsuka, PDL, Pharmacosmos, Pfizer, Procter & Gamble, Prometheus, Sandoz, Schering-Plough, Second Genome, Setpointmedical, Takeda, Therakos, Tigenix, UCB, Zealand, Zyngenia, and 4SC, P. Moayyedi: None Declared, S. Yusuf: None Declared

Comparison of three PET methods to assess peritoneal membrane transport

The peritoneal equilibration test (PET) is the most widespread method for assessing water and solute transport across the peritoneal membrane. This study compared three methods: traditional PET (t-PET), mini-PET, and modified PET (mod-PET). Non-diabetic adults (n=21) who had been on peritoneal dialysis (PD) for at least three months underwent t-PET (glucose 2.5%-4 h), mini-PET (glucose 3.86%-1 h), and mod-PET (glucose 3.86%-4 h) to determine dialysate-to-plasma concentration ratio (D/P) for creatinine and dialysate-to-baseline dialysate concentration ratio (D/D0) for glucose. Agreement between methods regarding D/P creatinine and D/D0 glucose was assessed using analysis of variance (ANOVA), Pearson's correlation coefficient, and Bland-Altman analysis. D/P creatinine differed between t-PET and mini-PET (P<0.001) and between mod-PET and mini-PET (P<0.01) but not between t-PET and mod-PET (P=0.746). The correlation of D/P creatinine with t-PET vs mod-PET was significant (r=0.387, P=0.009) but not that of t-PET vs mini-PET (r=0.088, P=0.241). Estimated bias was −0.029 (P=0.201) between t-PET and mod-PET, and 0.206 (P<0.001) between t-PET and mini-PET. D/D0 glucose differed between t-PET and mod-PET (P=0.003) and between mod-PET and mini-PET (P=0.002) but not between t-PET and mini-PET (P=0.885). The correlations of D/D0 glucose in t-PET vs mod-PET (r=−0.017, P=0.421) or t-PET vs mini-PET (r=0.152, P=0.609) were not significant. Estimated bias was 0.122 (P=0.026) between t-PET and mod-PET, and 0.122 (P=0.026) between t-PET and mini-PET. The significant correlation of D/P creatinine between t-PET and mod-PET suggested that the latter is a good alternative to t-PET. There was no such correlation between t-PET and mini-PET.

Reduced lipoapoptosis, hedgehog pathway activation and fibrosis in caspase-2 deficient mice with non-alcoholic steatohepatitis

OBJECTIVE

Caspase-2 is an initiator caspase involved in multiple apoptotic pathways, particularly in response to specific intracellular stressors (eg, DNA damage, ER stress). We recently reported that caspase-2 was pivotal for the induction of cell death triggered by excessive intracellular accumulation of long-chain fatty acids, a response known as lipoapoptosis. The liver is particularly susceptible to lipid-induced damage, explaining the pandemic status of non-alcoholic fatty liver disease (NAFLD). Progression from NAFLD to non-alcoholic steatohepatitis (NASH) results, in part, from hepatocyte apoptosis and consequential paracrine-mediated fibrogenesis. We evaluated the hypothesis that caspase-2 promotes NASH-related cirrhosis.

DESIGN

Caspase-2 was localised in liver biopsies from patients with NASH. Its expression was evaluated in different mouse models of NASH, and outcomes of diet-induced NASH were compared in wild-type (WT) and caspase-2-deficient mice. Lipotoxicity was modelled in vitro using hepatocytes derived from WT and caspase-2-deficient mice.

RESULTS

We showed that caspase-2 is integral to the pathogenesis of NASH-related cirrhosis. Caspase-2 is localised in injured hepatocytes and its expression was markedly upregulated in patients and animal models of NASH. During lipotoxic stress, caspase-2 deficiency reduced apoptosis, inhibited induction of profibrogenic hedgehog target genes in mice and blocked production of hedgehog ligands in cultured hepatocytes.

CONCLUSIONS

These data point to a critical role for caspase-2 in lipid-induced hepatocyte apoptosis in vivo for the production of apoptosis-associated fibrogenic factors and in the progression of lipid-induced liver fibrosis. This raises the intriguing possibility that caspase-2 may be a promising therapeutic target to prevent progression to NASH.

THE FINE STRUCTURE OF ASTROCYTES IN THE CEREBRAL CORTEX AND THEIR RESPONSE TO FOCAL INJURY PRODUCED BY HEAVY IONIZING PARTICLES

Normal and reactive astrocytes in the cerebral cortex of the rat have been studied with the electron microscope following focal alpha particle irradiation. The presence of glycogen and approximately 60-A fibrils identify astrocyte cytoplasm in formalin-perfused tissue. The glycogen particles facilitate the identification of small processes and subpial and perivascular end-feet. Both protoplasmic and fibrous astrocytes contain cytoplasmic fibrils and should be distinguished on the basis of the configuration of their processes and their distribution. Acutely reactive astrocytes are characterized by a marked increase in the number of glycogen granules and mitochondria from the first day after irradiation. These cells later hypertrophy and accumulate lipid bodies and increased numbers of cytoplasmic fibrils. The glial "scar" consists of a greatly expanded volume of astrocyte cytoplasm filled with fibrils and displays no signs of astrocyte death, reversion to primitive forms, or extensive multiplication.

Characterization of [125I]ZM 241385 binding to adenosine A2A receptors in the pineal of sheep brain

Adenosine is a ubiquitous neuromodulator and homeostatic regulator that exerts its physiologic actions through activation of A(1), A(2A), A(2B) and A(3) adenosine receptor subtypes. In the central nervous system, adenosine's action in neurons is manifested in its modulation of tonic inhibitory control. Adenosine released in the brain during hypoxia has critical depressant effects on breathing in fetal and newborn mammals, an action suggested to be mediated by A(2A) receptors in the posteromedial thalamus. In an effort to more accurately define the spatial distribution of adenosine A(2A) receptors in fetal sheep diencephalon, we have used a receptor autoradiographic technique utilizing an iodinated radioligand [(125)I]ZM 241385, which has greater sensitivity and resolution than the tritiated compound. The distribution of ligand binding sites in the fetal sheep diencephalon indicated that the highest levels of binding were in select thalamic nuclei, including those implicated in hypoxic depression of fetal breathing, and the pineal. Given the high density of labeled A(2A) receptors in the pineal, these sites were characterized more fully in homogenate radioligand binding assays. These data indicate that [(125)I]ZM 241385 binding sites display a pharmacological signature consistent with that of adenosine A(2A) receptors and are expressed at similar levels in fetal, lamb and adult ovine brain. The adenosine A(2A) receptor pharmacologic signature of the [(125)I]ZM 241385 binding site in pineal cell membranes generalized to the site characterized in membranes derived from other portions of the lamb thalamus, including the sector involved in hypoxic inhibition of fetal breathing. These results have important implications for the functional roles of adenosine A(2A) receptors in the thalamus and pineal of sheep brain.

Inflammation-induced changes in primary afferent-evoked release of substance P within trigeminal ganglia in vivo

Substance P (SP) is synthesized in a subset of nociceptive sensory neurons and is released from their peripheral and central terminals. Here we demonstrate with the use of in vivo microdialysis and radioimmunoassay techniques that SP is also released within trigeminal ganglia following intraganglionic application of KCl, veratridine or capsaicin, and after electrical stimulation of peripheral afferent fibers. Both the basal and KCl-evoked release of SP are shown to be dependent on extracellular calcium. Using the turpentine-induced model of unilateral orofacial inflammation we also show that both the basal and KCl-evoked release of SP within trigeminal ganglia are greatly increased on the inflamed side 48 h after induction of inflammation. Coupled with previous demonstrations of excitatory effects of SP on sensory neurons, these results suggest that SP fulfils the role of a non-synaptically released diffusible chemical messenger that may modulate the somatic excitability of neurons within sensory ganglia in inflammatory pain states.

Thalamic lesions dissociate breathing inhibition by hypoxia and adenosine in fetal sheep

The effects of diencephalic lesions on respiratory responses to intra-arterially infused adenosine (ADO) were determined in chronically catheterized fetal sheep (>0.8 term). These studies were designed to test the hypothesis that the inhibitory effects of ADO on fetal breathing, like those of hypoxia, are mediated by the parafascicular nuclear complex (Pf) of the posteromedial thalamus. ADO inhibited breathing [control (C): 26 +/- 2.6, ADO: 4 +/- 1 min/h] in normal fetuses and in a fetus with a lesion that virtually destroyed the thalamus but left intact most of Pf. Neuronal lesions in the diencephalon, produced by injecting ibotenic acid, abolished the inhibitory effects of ADO on breathing (C: 31 +/- 5.1, ADO: 30 +/- 4.5 min/h) when the lesions encompassed Pf or the sector immediately rostral to Pf that retained the capacity to regulate hypoxic inhibition. Smaller lesions created by the insertion of needles also eliminated the depressant effects of ADO when disruptions were within Pf or a rostral component of the thalamic cortical activating system. It is concluded that 1) a medial thalamic sector is critically involved in ADO-induced apnea and 2) ADO-dependent and ADO-independent mechanisms mediate hypoxic inhibition.

Foreign body in the medial pterygoid space

Retained intra-oral foreign bodies have been reported rarely in the literature. A case of a foreign body retained for an extended period of time in the medial pterygoid space is reported here.

Thalamic locus mediates hypoxic inhibition of breathing in fetal sheep

The effects of lesions rostral to the brain stem on breathing responses to hypoxia were determined in chronically catheterized fetal sheep (>0.8 term). These studies were designed to test the hypothesis that the diencephalon is involved in hypoxic inhibition of fetal breathing. As in normal fetuses, hypoxia inhibited breathing with transection rostral to the thalamus or transection resulting in virtual destruction of the thalamus but sparing most of the parafascicular nuclear complex. Neuronal lesions were produced in the fetal diencephalon by injecting ibotenic acid through cannulas implanted in the brain. Hypoxic inhibition of breathing was abolished when the lesions encompassed the parafascicular nuclear complex but was retained when the lesions spared the parafascicular nuclear region or when the vehicle alone was injected. A new locus has been identified immediately rostral to the midbrain, which is crucial to hypoxic inhibition of fetal breathing. This thalamic sector involves the parafascicular nuclear complex and may link central O2-sensing cells to motoneurons that inhibit breathing.

Source of extracellular brain adenosine during hypoxia in fetal sheep

Microdialysis was performed to determine whether hypoxia increases fetal brain adenosine (ADO) concentration through dephosphorylation of extracellular 5'-adenosine monophosphate (5-AMP). Hypoxia (fetal PaO2 approximately 14 Torr) increased fetal brain ADO levels approximately two-fold when the probes were perfused with synthetic cerebrospinal fluid (CSF) containing inhibitors of the nucleoside transporter but not with this solution plus a blocker of ecto-5'-nucleotidase (AOPCP). The hypoxia-induced rise in fetal brain ADO concentrations depends critically upon the hydrolysis of extracellular 5'-AMP.

Warm-sensitive afferent splanchnic C-fiber units in vitro

Receptive fields of 41 slowly conducting sensory fibers were located using a thermal (warm) search stimulus in an in vitro splanchnic nerve-mesentery preparation. Warm-sensitive receptive fields were punctate and were densest in the region surrounding the prevertebral ganglia, an area with prominent deposits of brown adipose tissue, where the abdominal aorta branches into the major trunks supplying the abdominal viscera. Impulse activity was recorded while applying a warm stimulus to identified receptive fields (RFs). The warm stimulus consisted of a warming ramp (10-15 degrees C in 1-2 s to a 42-49 degrees C peak temperature) followed by a 10- to 30-s period during which the RF was maintained at this peak temperature (plateau phase). Eighty percent (33/41) of warm-sensitive units responded to warming with discharge comprising both a phasic and a tonic component (slowly adapting warm-sensitive, or SA-W, units). The remainder (8/41) responded with only phasic discharge (rapidly adapting warm-sensitive, or RA-W, units). Units' adaptation characteristics were consistent from trial to trial and when applying stimuli from different positions. Fifty percent of SA-W units (8/16) and 17% of RA-W units (1/6) were activated by transient exposure to 9-90 nM bradykinin (BK). Twenty-seven percent (9/33) of SA-W units and 12% (1/8) of RA-W units were activated by probing their RF with von Frey hairs with bending forces < 10 mN (approximately 1 g equivalent mass). An additional five SA-W units tested were activated by strong mechanical stimuli (compression with a metal probe or firm stretching). No BK-responsive warm-sensitive units were activated by von Frey probing < 10 mN, but two (both SA-W) responded to strong mechanical stimuli. In six SA-W units and one RA-W unit, the number of impulses evoked by warming approximately 5 min after exposure to BK was > 2 SD greater than the mean pre-BK response, indicating sensitization. This sensitization was transient, the response to warming returning to within one standard deviation of the pretrial mean or less over the course of the next 5-10 min. Changes in background activity, mechanical sensitivity, BK sensitivity, and BK-induced sensitization were noted in various splanchnic units over the course of prolonged observations, suggesting that these indices may not reliably distinguish unit type, but instead may indicate the functional state of the sense organ. Splanchnic neurons responsive to the intense warming used in the present in vitro experiments may participate in the cardiovascular responses observed in vivo in heat-stressed rats. The dense distribution of warm-receptive fields in the vicinity of the celiac-superior mesenteric ganglionic complex is consistent with the localization of splanchnic thermosensitive units previously noted in vivo in the rabbit.

GAP-43 mRNA and calcitonin gene-related peptide mRNA expression in sensory neurons are increased following sympathectomy

Sympathectomy has been shown to result in an increased density of fibers immunoreactive for sensory peptides in peripheral targets innervated by both sensory and sympathetic neurons, providing evidence for functional interactions between sympathetic and sensory systems. These findings provided the background for examining the hypothesis that axonal outgrowth is induced from sensory neurons following sympathectomy. We examined the expression of GAP-43 mRNA, a specific marker for axonal outgrowth, in cervical (C3, C7, C8) and thoracic (T1, T2) dorsal root ganglia (DRG) of the rat following bilateral removal of the superior cervical ganglion, to assess whether the described increases in peptidergic afferent fibers reflected axonal outgrowth. In situ hybridization was used with 35S labeled riboprobes complementary to GAP-43 mRNA, and to calcitonin gene-related peptide (CGRP) mRNA, a marker for a major subset of thin-fiber sensory neurons. The density of GAP-43 mRNA nearly doubled by 18 h following sympathectomy and reached a threefold increase by 3 days. By 45 days following surgery, the GAP-43 mRNA level was still nearly twice that of normal animals, CGRP immunoreactivity was also examined: the density of fibers in the iris and cornea of sympathectomized animals was considerably greater from two weeks to 45 days following surgery, than in sham-operated controls. Concomitantly, there was a slight but significant increase in CGRP mRNA expression in T1 and C3 DRG 14 days postsympathectomy. Quantitative computerized image analysis demonstrated that GAP 43 mRNA expression in sympathectomized animals was 1.5 times greater in medium-sized DRG neurons and almost fourfold greater in small DRG neurons than in control rats. These results indicate that sympathetic denervation elicits axonal outgrowth in the population of sensory neurons that give rise to the small unmyelinated and thinly myelinated axons of peripheral nerves.

Wound healing in orthopaedic procedures for Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome is a triad of cutaneous hemangiomas, varicose veins, and hypertrophy of soft tissue and bone; when combined with arteriovenous fistulas, the syndrome is known as Klippel-Trenaunay-Weber syndrome. Orthopaedic surgical management of localized limb-length discrepancy or hypertrophy in these conditions is frequently indicated, especially in the lower limb. Forty orthopaedic procedures in 21 patients were retrospectively reviewed. Nine (22.5%) wound complications were identified in this study group. All the complications were associated with transverse amputations. All required significant further treatment and extension of hospital stay. Wound complications should be anticipated in patients with Klippel-Trenaunay syndrome having orthopaedic surgical procedures, especially terminal amputations.

H2O2 sensitivity of afferent splanchnic C fiber units in vitro

1. Single-unit impulse activity evoked by transient, focal application of hydrogen peroxide (H2O2) to identified visceral receptive fields has been characterized in an in vitro rat splanchnic nerve-mesentery preparation. In addition to H2O2 responsiveness, units were characterized in terms of sensitivity to mechanical stimuli, warming, and bradykinin. 2. Mesenteric receptive fields of single splanchnic afferent C fibers in vitro were located with the use of warm (approximately 45 degrees C saline) or mechanical search stimuli. After delimitation of the warm-sensitive and/or mechanosensitive receptive field, units were tested for responsiveness to transient, focal application of H2O2. Microliter volumes (usually 1 microliter) of H2O2 (88-880 mM) evoked responses in 25 of 42 (60%) units with identified warm-sensitive and/or mechanosensitive receptive fields, and in an additional 10 units for which H2O2 was the only effective stimulus. 3. Tachyphylaxis to repeated H2O2 stimulation was observed with interstimulus intervals <30 min, but did not indicate irreversible inactivation of the terminal, because 1) during this period warm and mechanical stimuli elicited responses equal to or greater than those before H2O2 treatment, and 2) H2O2 sensitivity was restored after units were allowed to recover. 4. Eight units unresponsive to an initial dose of H2O2 responded vigorously to a repeated application at the same site, suggesting a potentiating effect of prior H2O2 exposure. 5. Sixty-two percent (8 of 13) of H2O2-responsive units, but no (0 of 6) H2O2-unresponsive units responded to transient, focal bradykinin (9-90 nM) application. 6. An indirect mode of H2O2-evoked afferent excitation in some units was suggested by several observations, including the prolonged (up to 8 min) duration of the response of some units to transient H2O2 application, and the occasionally long (>2 min) response latencies to focal application of H2O2 to defined receptive fields. 7. Excitation of splanchnic neurons by H2O2 may be relevant to the modulation of reactive oxygen species production by immunocompetent cells, because sensory neuropeptides contained in these afferent fibers are known to influence the respiratory burst of macrophages and neutrophils.

Evidence for uptake of vital dye by activated rat peritoneal mast cells: an in vitro imaging study

Uptake of material from surrounding medium by activated rat peritoneal mast cells (PMCs) was studied using in vitro peritoneal eluate cells, the vital fluorescent dye sulforhodamine B (SFRM-B), secretagogue compound 48/80, and an imaging technique. PMCs, which undergo different states of degranulation, are shown to possess the ability to take up (by endocytosis) SFRM-B in an activity-dependent manner. The endocytosed dye is incorporated in the granules and can be discharged into the medium when the cells are reactivated. Both the uptake and the discharge processes are calcium-dependent. The reactivity of mast cells to secretagogue is not altered by the application of the dye. SFRM-B, a negatively charged, nonspecific protein stain, displays greater photostability and less leakage than the positively charged acridine orange, and its fluorescence persists for hours, whereas acridine orange fluorescence fades within 1 min when exposed to ultraviolet illumination. The fluorescent image of the dye-loaded mast cells can be preserved overnight in a container at room temperature. SFRM-B elicits no detectable damaging influence on the activated afferent discharge of splanchnic afferent nerve fibers with mesenteric terminals. This enables the use of SFRM-B for studying the interactions between mesenteric afferent terminals and their surrounding mast cells.

Some sensory neurons express neuropeptide Y receptors: potential paracrine inhibition of primary afferent nociceptors following peripheral nerve injury

Neuropeptide Y (NPY) has been suggested to exert antinociceptive actions by inhibiting the release of neurotransmitters from trigeminal and dorsal root ganglia (DRG) neurons, but the site of direct NPY action in vivo and the NPY receptor subtype mediating these effects are unknown. 125I-peptide YY (PYY) was used to localize and characterize NPY receptor binding sites in trigeminal ganglia, DRG, and spinal cord of the rat, rabbit, and monkey. In the rat, rabbit, and monkey, 5-20% of trigeminal ganglia and DRG neurons express NPY binding sites. Unilateral cuff-induced neuropathy or transection of the rat sciatic nerve did not significantly alter the density or number of DRG neurons expressing NPY receptors. A unimodal size distribution for L4 and L5 DRG neurons expressing NPY binding sites in the rat was determined, with a mean cross-sectional area of 947 microns 2. In the spinal cord the highest concentration of NPY receptors is found in laminae I, II, V, X, and Onuf's nucleus. Pharmacological experiments using selective Y1 and Y2 receptor antagonists suggest that Y2 is the prominent NPY receptor subtype expressed in trigeminal ganglia neurons, DRG neurons, and spinal cord. Previous studies have demonstrated that a population of large-diameter, presumably myelinated primary afferents express NPY after peripheral nerve injury. NPY released from these injured large-diameter DRG neurons may act in a paracrine fashion to block the transmission of nociceptive information from the small- and medium-diameter DRG neurons that constitutively express NPY receptors. NPY receptors are therefore uniquely positioned to inhibit primary afferent nociceptors directly, especially after peripheral nerve injury.

Distribution of GAP-43 mRNA in the adult rat brain

Regional distribution of gene expression of the axonal growth-associated protein, GAP-43, was studied in adult rat brains by in situ hybridization autoradiography to determine the features of mature neuronal populations that synthesize GAP-43 protein. Such synthesis appears to correlate with axonal growth during maturation and regrowth after axotomy. In most adult neurons, the sharp decline in GAP-43 gene expression implies a reduced capacity for axonal growth. Neurons capable of extending axonal knobs in the absence of injury may indicate a "plasticity" underlying dynamic processes of interaction between neurons and their synaptic targets. Antisense and sense (control) riboprobes were used on serial sections in the three principal axes, and the magnitude of hybridization signal was examined to determine regional patterns. GAP-43 mRNA levels are pronounced in diverse neuronal groups including the locus coeruleus, raphé nn., dopaminergic nigral and ventral tegmental nn., mitral cells, hippocampal CA3, inferior olivary n., vagal motor n. and other parasympathetic preganglionic neurons, select thalamic midline and intralaminar nn., several specific nn. of the hypothalamus and basal forebrain, the granular layer of cerebellar cortex, the infragranular neocortex, and the granular olfactory paleocortex; there is a substantial range in the magnitude of expression. Regions revealing minimal signal include most thalamic sensory relay nuclei, the granule neurons of the olfactory bulb and dentate gyrus, and the caudate and putamen. Possible concomitants of GAP-43 expression include regulation of ion flux and neurotransmitter release. Those neurons with long, extensively dispersed and numerous synaptic connections display the strongest signals and may possess the greatest propensity for continuous growth and turnover of their axon terminals, in contrast to short-axon and specific projection neurons exhibiting minimal levels. These data may enable inferring which populations display normal or experimentally induced axonal growth.

GAP-43 mRNA localization in the rat hippocampus CA3 field

Gene expression of the axonal growth-associated protein, GAP-43, has been studied in the adult rat brain by in situ hybridization histochemistry. This protein is synthesized at high levels in neuronal somata in immature and regenerating neurons, but after establishment of mature synaptic relations its synthesis generally declines sharply, thus providing a marker denoting propensity for exhibiting synaptic plasticity. Detailed examination of the distribution of mRNA for GAP-43 in rat hippocampus is selectively and robustly expressed in the pyramidal neurons of field CA3 and, to a lesser extent, the polymorph neurons of the hilus of the dentate gyrus. Additional hippocampal regions of moderate expression include the tenia tecta and the subicular and entorhinal fields, but CA1 and CA2 are strikingly lower in signal. The significance of this pattern of localization is considered in the context of the phosphorylation of GAP-43 and its role in influencing synaptic events underlying the establishment and maintenance of long-term potentiation and plasticity in the hippocampus.

Fine structural organization of the ependymal region of the paraventricular nucleus of the rat thalamus and its relation with projection neurons

The ependymal lining of the diencephalic third ventricle is known to exhibit significant variation in zonal architecture and the relations of neurites to the ventricular surface in different regions remains obscure. The present study explores the fine structural organization of the ependymal region of the thalamic paraventricular nucleus. Methodology was developed for tracing neurites of cells retrogradely labelled with horseradish peroxidase based on our recent observation that paraventricular neurons projecting to the amygdaloid complex cluster near the ventricle and emit numerous dendrites extending toward the ependymal surface. A relatively uniform population of cuboidal 'pale' ependymocytes dominates the ventricular lining of the thalamic paraventricular nucleus, although a few 'dark' ependymocytes are interspersed. The subependymal region displays a variety of glial elements. Dendrites of thalamic paraventricular projection neurons terminate in proximity to the ependymal layer from which they are generally separated by thin cytoplasmic processes of putative astrocytes, and few indent the basal portion of ependymal cells. Thin 'terminal' (i.e., serially traced) horseradish peroxidase-labelled dendrites filled with lipid and lysosome-like dense bodies were often enveloped by astrocyte membrane whorls. This feature may constitute a reactive glial response in horseradish peroxidase-labelled dendritic terminals. A distinctive arrangement of tortuous astrocyte leaflets was insinuated between the basal portion of ependymocytes in a zone exhibiting numerous caveolae, apparently isolating neurites from direct contact with the cerebrospinal fluid. These findings indicate that the ependymal region of the thalamic paraventricular nucleus is not characterized by those features of the basal third ventricle suspected to confer neuroendocrine interaction between neurons and cerebrospinal fluid. The structural arrangement between ependymocytes and thalamic paraventricular projection cells indicate a specialized relation of these neurons with the ependymal interface, but apparently not directly with the overlying cerebrospinal fluid.

Sources of anterior gastric vagal efferent discharge in rats: an electrophysiological study

The source of vagal efferent discharge (VED) in the anterior branch of the gastric vagus was investigated in urethane-chloralose anesthetized rats using successive and selective vagal cuts. After cutting the right cervical vagus, the basal VEDs were increased in 15 out of 21 cases by 4-53% (median 18%). After both cervical vagi were cut, VEDs were reduced by 10-95% (median 90%) in 14 of 17 experiments and a subcervical basal VED was observed in all rats. Additional cut of the distal end of the anterior gastric branch did not induce a consistent effect. A small segment of subdiaphragmatic anterior gastric vagus (4-5 mm) was further isolated by a fourth cut at the proximal end of the anterior gastric vagus; abolition of the subcervical VED occurred in only 4 of 14 successful cuts whereas in the other 10 experiments, the VED was reduced by 38-94% (median 87%). Histological examination revealed the presence of neurons in a paraganglion lying within the isolated nerve segment. These findings indicate that the stomach not only receives VED descending directly from medullary vagal motor neurons (about 90%), but also (approximately 10%) from neural elements located between subcervical to upper abdomen levels (the 'subcervical VED') and/or between the bifurcation of the accessory celiac branch to the gastro-esophageal junction (the 'residual VED'). In rats there is little crossed gastric vagal innervation, in agreement with anatomical observations, although there is a robust inhibitory influence from contralateral vagal afferents on medullary vagal motor neurons.

Selective neuronal glycoconjugate expression in sensory and autonomic ganglia: relation of lectin reactivity to peptide and enzyme markers

Several plant lectins were used to characterize the cell-surface carbohydrates expressed on sensory ganglion cells and their central terminals in the spinal cord dorsal horn. In the rat, galactose-terminal glycoconjugates on a large subpopulation of small neurons whose central axons project to the substantia gelatinosa were demonstrated with the alpha-D-galactose-specific Griffonia Simplicifolia I-B4 (GSA) lectin. This neuron subset was labelled by alternative D-galactose-, N-Acetylgalactosamine-, and beta Gal(1,3)NAcGal-binding lectins. Similar GSA lectin reactivity was also illustrated in selected peripheral autonomic, gustatory and visceral sensory and enteric neurons, and the accessory olfactory bulb. The sensory neuron-specific isoenzyme, fluoride-resistant acid phosphatase (FRAP) co-localized with the GSA lectin, as did the monoclonal antibody (MAb) 2C5, which is directed against a lactoseries carbohydrate constituting a backbone structure of ABH human blood group antigens. In contrast, calcitonin gene-related peptide-immunoreactivity (CGRP-IR), used as a representative marker of peptidergic neurons, exhibited limited co-localization with GSA. A polyclonal anti-rat red blood cell (RBC) antibody co-localized with GSA, suggesting that lectin-reactive carbohydrates on rat sensory neurons are related to rat RBC antigens. In the human spinal cord, the L-fucose-binding Ulex europaeus-I (UEA) lectin also labelled the substantia gelatinosa; in rabbit, a small sensory ganglion cell subset and the spinal cord substantial gelatinosa was co-labelled by both the GSA and UEA lectins. These studies illustrate significant lectin-reactive cell surface carbohydrate expression by non-peptidergic, FRAP(+) sensory ganglion cells in the rat, and provide a means for visualizing the extensive, non-peptidergic, small sensory ganglion cell subpopulations, probably including a substantial proportion of nociceptive and unmyelinated peripheral axons.

Analysis of taste bud innervation based on glycoconjugate and peptide neuronal markers

Primary gustatory neurons and their peripheral and central processes were evaluated histochemically in the geniculate and petrosal cranial nerve ganglia, lingual fungiform taste buds, and the nucleus of the solitary tract (NST) using 1) the plant lectin Griffonia simplicifolia I-B4, which binds specifically to D-galactose residues and selectively labels primarily nonpeptide-containing peripheral somatosensory neurons, and 2) calcitonin gene-related peptide immunoreactivity (CGRP-IR), which labels most peptidergic somatosensory neurons. Lectin reactivity was expressed by the vast majority of geniculate and petrosal ganglion cells, while CGRP-IR labeled very few cells. Peripherally, gustatory intragemmal axons penetrating fungiform taste buds were labeled only by the lectin and were depleted following chorda tympani transection. However, both lectin-labeled and CGRP-IR subpopulations of somatosensory perigemmal axons surrounding the taste buds were observed and were eliminated by section of the lingual nerve. The differing brainstem projection patterns of lectin-reactive vs. CGRP-IR central axons reflected their distinct ganglionic origins and the differential distributions of lectin reactivity and CGRP-IR among taste buds. Central lectin-reactive terminals were found throughout the entire rostrocaudal extent of the NST, including its rostral lateral "gustatory" zone; the extensive lectin-reactive visceral afferent projection can be presumed to have originated mainly from the large proportion of lectin-labeled neurons in the nodose ganglion. The lectin also prominently and selectively labeled the area postrema. CGRP-IR central terminals, however, was relatively sparse and restricted primarily to the caudal and medial "visceral" divisions of the NST. The results are discussed with respect to the possible functional implications of cell surface glycoconjugate expression by gustatory axons innervating taste bud receptor cells of the tongue.

Calcitonin-gene-related-peptide-immunoreactive innervation of the rat head with emphasis on specialized sensory structures

The distribution of calcitonin-gene-related peptide-like immunoreactivity (CGRP-IR) was studied in sections of decalcified rat head and selected whole-mount preparations in order to address the complex peptidergic innervation patterns in peripheral cephalic specialized zones and to examine neuronal ganglia in situ. Labeled neuron somata in trigeminal, glossopharyngeal, and vagal ganglia comprised a large proportion of small to medium size type B ganglion cells. Parasympathetic ganglia (ciliary, otic, sphenopalatine, submandibular) revealed a small population of labeled somata and numerous perisomatic IR axons, whereas sympathetic ganglion cells (superior cervical) were devoid of label though richly innervated by perisomatic IR axons. The gustatory geniculate ganglion contained only a few labeled neurons and axons. Coarse peripheral CGRP-IR axons were traced to skeletal muscle motor end plates (e.g., lingual, tensor tympani, etc.), and thin sensory axons most densely innervated the cornea, iris, general integument, all mucosal epithelia lining the tympanic, nasal, sinus and oropharyngeal cavities, and the cerebral meninges. Blood vessels, glands, ducts, and their orifices were often heavily innervated, and specific specializations and exceptions are discussed. Distinctive patterns of IR innervation characterized the various specialized sensory systems, including 1) cochlear and vestibular hair cells; 2) lingual, palatal, oropharyngeal, and laryngoepiglottal taste buds; 3) main olfactory epithelium and axons projecting to glomeruli in specific sectors of main olfactory bulb; 4) septal-olfactory organ; 5) vomeronasal organ; and 6) the nervus terminalis system. Secretory epithelia (ciliary body, choroid plexus, and stria vascularis) were notably lacking in CGRP-IR. Despite the multiplicity of functionally distinct CGRP neuronal and axonal populations, certain generalizations merit consideration. The extensive innervation of chemosensory nasal and oral epithelia may contribute to specific chemical sensitivities (e.g., relating to olfactory and gustatory senses) as well as evoking "nociceptive" responses to chemical irritants as part of a "common chemical sense." An efferent role for some of these peptidergic afferent axons may also be inferred from their specific distributions. Sites involved in regulating access to and sensitivity of sense organs to external stimuli (e.g., cochlear and vestibular hair cells, taste bud orifices, and main olfactory epithelium) are heavily innervated. Other IR axons are in position to exert control over airflow through nasal turbinates, glandular secretion, blood circulation, and duct transport systems.(ABSTRACT TRUNCATED AT 400 WORDS)

Peripheral patterns of calcitonin-gene-related peptide general somatic sensory innervation: cutaneous and deep terminations

The distribution of calcitonin-gene-related peptide (CGRP) immunoreactivity (IR) was studied in peripheral tissues of rats. The ganglionic origin, somatosensory nature, and anatomic relations of this thin-axon population were evaluated with particular emphasis on possible nociceptive roles. In animals untreated with colchicine, CGRP-IR is found in a vast proportion of small- and medium-diameter sensory ganglion cells that give rise to numerous thinly myelinated and unmyelinated axons that display CGRP-IR throughout the body. The integumentary innervation consists, in part, of an extensive subpapillary network largely traced to dermal blood vessels, sweat glands, and "free" nerve endings, some of which are found within regions containing only mast cells, fibroblasts, and collagen. Dermal papillae contain CGRP-IR axons surrounding each vascular loop; other papillary axons end freely or occasionally surround Meissner corpuscles. Intraepithelial axons enter glabrous epidermal pegs, branching and exhibiting terminals throughout the stratum spinosum. A similar pattern is found in hairy skin with additional innervation entering the base and surrounding the lower third of each hair follicle, but apparently not supplying sebaceous glands and arrector pili muscle. Axons innervating nonkeratinized oral epithelium are similar or greater in number and distribution compared to epidermis, often with more extensive branching. The high density of intraepithelial CGRP-IR innervation does not appear to correlate with the sensitive mechanoreceptor-based increase in spatial sensory discriminative capacities in the distal portions of the limb. In deep somatic tissues, CGRP-IR is principally related to vasculature and motor end plates of striated muscle, but there is an extensive network of thin axons within bone, principally in the periosteum, and focally in joint capsules, but not in relation to muscle spindles or tendon organs. These findings, together with the distribution in cranial tissues described in an accompanying paper (Silverman and Kruger: J. Comp. Neurol. 280:303-330, '89), are considered in the context of a "noceffector" concept incorporating the efferent role of these sensory axons in various tissues. It is suggested that involvement in tissue maintenance and renewal during normal function, as well as following injury, may predominate over the relatively infrequent nociceptive role of this peptidergic sensory system.

Calcitonin gene-related peptide (CGRP) in the rat central nervous system: patterns of immunoreactivity and receptor binding sites

The distribution of immunoreactive (IR) axons and neurons in the rat central nervous system (CNS) has been studied with an antiserum directed against the C-terminal sequence of rat a-calcitonin gene-related peptide (CGRP) and a durable peroxidase reaction product for detailed analysis in relation to normal cytoarchitecture. These materials were studied and illustrated in the three principal axes in relation to cell-stained adjacent sections in normal as well as colchicine- and capsaicin-treated animals, although no fundamental differences in pattern were evident in neurotoxin-treated rats. The patterns of CGRP-IR were then compared with autoradiograms of specific, high affinity receptor binding sites for 125I-human a-CGRP. CGRP-IR labeling in motor systems includes the vast majority of motoneurons, enabling facile identification of isolated 'accessory' populations. Preganglionic parasympathetic nuclei revealed only labeling of a small proportion of neurons. By contrast, the sensory systems revealed a diversity of labeling patterns precluding simple generalizations. Peripheral input ranges from extensive labeling of thin somatic afferents, feeble to moderate gustatory and olfactory afferents to a total absence of auditory afferents, yet IR axons and neurons can be found in selective distribution within each of these sensory systems. Patterns of IR in various integrative centers, e.g. cerebellum, basal ganglia and hypothalamus, reveal selectivity that fails to conform to conventional descriptions of functional systems. Some regions display unexpected patterns, e.g. vertical stripes in cerebellar cortex. CGRP receptor binding sites (RB) are found in many of the sites where IR axons terminate and in some cases, e.g. motor neurons, which express intraneuronal IR. The main sensory systems reveal a variety of RB patterns, only a few of which can be related to sites of IR axon terminals. Many apparent 'mismatches' between IR and RB are illustrated and discussed in the context of functional peptide expression or in quasi-hormonal terms. It is suggested that the principle of CGRP-IR axon distribution in peripheral tissues, where synapses are lacking, might also apply to the CNS and that neither the locus of IR-axon terminals nor RB sites need indicate transmitter action for impulse information transfer. CGRP is a widely distributed neuromodulator probably subserving a role in both synaptic and metabolic regulation, depending on the specific requirements of the diverse distribution of its receptors.

Corticothalamic and corticotectal somatosensory projections from the anterior ectosylvian sulcus (SIV cortex) in neonatal cats: an anatomical demonstration with HRP and 3H-leucine

Corticothalamic and corticotectal projections from the anterior ectosylvian sulcus (AES) in neonatal cats were studied with anterograde and retrograde neuroanatomical techniques. When the injection site was relatively restricted to the sulcal walls and fundus of the rostral AES (i.e., the SIV cortex), heavy ipsilateral thalamic label was observed in the medial subdivision of the posterior group, in the suprageniculate nucleus, and in the external medullary lamina. No terminal label was seen in the contralateral thalamus although the contralateral homotopic cortex was heavily labeled. Within the ventrobasal complex (VB), dense axonal label was observed in fascicles that traversed VB, but only light terminal label was observed within VB itself. However, in cases where the tracer spread into adjacent SII, terminal label in VB was pronounced. Similarly, when the injection site extended into auditory cortex, terminal label was observed in the lateral and intermediate subdivisions of the posterior group. Rostral AES injections produced distinct, predominantly ipsilateral, terminal label in the superior colliculus that was distributed in two tiers: a discontinuous band in the stratum griseum intermedium and a more diffuse band in stratum griseum profundum. Caudally, dense terminal label was seen in the intercollicular zone and dorsolateral periaqueductal gray. When the injection site did not include rostral AES, no label was observed in the superior colliculus. Horseradish peroxidase injections into the superior colliculus of neonates produced retrogradely labeled neurons throughout the AES, but none was found on the crown of the gyrus where SII is located. Thus, the neonatal corticotectal somatosensory projection arises exclusively from AES and parallels that found in adults. These data indicate that the elaboration of a major descending somatosensory pathway from AES to the thalamus and midbrain is largely a prenatal event. The in utero anatomical maturation of the corticofugal projections from SIV cortex to the superior colliculus contrasts with the protracted postnatal development of the corticotrigeminal projections from SI cortex but is consistent with the mature anatomical state of ascending trigeminotectal projections.

Distribution of calcitonin gene-related peptide immunoreactivity in relation to the rat central somatosensory projection

The distribution of the neuropeptide calcitonin gene-related peptide (CGRP) was studied in relation to the known subcortical somatosensory pathways and contiguous systems in the central nervous system (CNS) of rats by using peroxidase histochemical methods in order to relate zones of immunoreactivity (IR) to cytoarchitecture. CGRP is the most ubiquitous peptide found to date in sensory ganglion cells: principally small and medium-size neurons emitting thin axons inferred to be largely nociceptive in function on the basis of the peripheral distribution of their terminals. Its apparent absence in sympathetic axons provides an especially useful sensory marker. The distribution of CGRP-IR axons displays remarkable selectivity at each level of the CNS. The trigeminal root distributes axons primarily to the pericornual layers (laminae I and II) of spinal V nucleus caudalis and to subnucleus oralis, evading the subnucleus interpolaris and contributing only few axons to principal V. Although there are only a few CGRP-IR somata at each level, heavily labeled axon trajectories can be traced to the nuclei of the solitary tract, the parabrachial nuclei, several sectors of the caudal medial thalamus, and the central nucleus of the amygdala. A sector of labeled neuron somata lies contiguous to each of these axon terminal zones, the largest of which is a thalamic nucleus containing cells of distinctive dendritic architecture extending from the periaqueductal gray across the posterior group nuclei to the peripeduncular nucleus, forming a linear array at the mesodiencephalic junction. The relation of CGRP-IR axonal distribution to spinothalamic, visceral, and gustatory systems is discussed in the context of a specialized "chemosensory" component of the thin-fiber somatosensory system.

Receptor binding sites for substance P, but not substance K or neuromedin K, are expressed in high concentrations by arterioles, venules, and lymph nodules in surgical specimens obtained from patients with ulcerative colitis and Crohn disease

Several lines of evidence indicate that tachykinin neuropeptides [substance P (SP), substance K (SK), and neuromedin K (NK)] play a role in regulating the inflammatory and immune responses. To test this hypothesis in a human inflammatory disease, quantitative receptor autoradiography was used to examine possible abnormalities in tachykinin binding sites in surgical specimens from patients with inflammatory bowel disease. Surgical specimens of colon were obtained from patients with ulcerative colitis (n = 4) and Crohn disease (n = 4). Normal tissue was obtained from uninvolved areas of extensive resections for carcinoma (n = 6). In all cases, specimens were obtained less than 5 min after removal to minimize influences associated with degradation artifacts and were processed for quantitative receptor autoradiography by using 125I-labeled Bolton-Hunter conjugates of NK, SK, and SP. In the normal colon a low concentration of SP receptor binding sites is expressed by submucosal arterioles and venules and a moderate concentration is expressed by the external circular muscle, whereas SK receptor binding sites are expressed in low concentrations by the external circular and longitudinal muscle. In contrast, specific NK binding sites were not observed in any area of the human colon. In colon tissue obtained from ulcerative colitis and Crohn disease patients, however, very high concentrations of SP receptor binding sites are expressed by arterioles and venules located in the submucosa, muscularis mucosa, external circular muscle, external longitudinal muscle, and serosa. In addition, very high concentrations of SP receptor binding sites are expressed within the germinal center of lymph nodules, whereas the concentrations of SP and SK binding sites expressed by the external muscle layers are not altered significantly. These results demonstrate that receptor binding sites for SP, but not SK or NK, are ectopically expressed in high concentrations (1000-2000 times normal) by cells involved in mediating inflammatory and immune responses. These data suggest that SP may be involved in the pathophysiology of inflammatory bowel disease and might provide some insight into the interaction between the nervous system and the regulation of inflammation and the immune response in human inflammatory disease.

Nonoverlapping thalamocortical connections to normal and deprived primary somatosensory cortex for similar forelimb receptive fields in chronic spinal cats

The fluorescent dye retrograde tracing technique, using fast blue in combination with fluorogold, was used to examine thalamocortical projections from the ventrobasal complex to primary somatosensory cortex in chronic spinal cats that sustained T12 cord transection at 2 weeks of age. Following cord transection at this age, it has been shown that forelimb afferents can excite the deprived hindlimb projection zone, in addition to the region of somatosensory cortex that they normally occupy (McKinley et al., 1987). These two regions of cortex are separated by over 10 mm, thus facilitating the determination of whether the forelimb representation in "hindlimb cortex" is derived from the sector of the ventrobasal complex of the thalamus representing the forelimb, hindlimb, or both. Injections of the two dyes into separate regions of the cortex that were excited by the same peripheral forelimb receptive fields produced single labeling of two nonoverlapping clusters of thalamic neurons. This finding suggests that the projections for these two areas are independent and distinct, and indicates that altered thalamocortical projections do not contribute the critical component underlying reorganizational changes observed at the cortical level after spinal cord transection. It is hypothesized that the degree of reorganization required to achieve the magnitude of change observed in the cortex must occur below the level of the thalamocortical relay.

Acid phosphatase as a selective marker for a class of small sensory ganglion cells in several mammals: spinal cord distribution, histochemical properties, and relation to fluoride-resistant acid phosphatase (FRAP) of rodents

Fluoride-resistant acid phosphatase (FRAP) activity as characterized in rat and mouse was studied in sensory ganglion and spinal cord of several mammals, using both the Gomori lead-ion capture and azo-dye coupling methods. FRAP was specifically localized to small- and medium-diameter primary afferent neurons and inner substantia gelatinosa of all nonrodent animals studied, including rabbit, cat, dog, monkey, cow, and human. In rabbit, sciatic nerve transection resulted in depletion of enzymatic activity in ipsilateral spinal cord dorsal horn in a pattern corresponding to the distribution of central terminals of the nerve. Further analysis of the substrate specificity and pH dependence of FRAP was carried out primarily in rat sensory ganglion and spinal cord; the enzyme was found to hydrolyze a wide variety of phosphomonoesters in a relatively nonselective manner at both pH 5 and pH 7, including 5'-nucleotides, phosphorylated amino acids, and several exogenous compounds. The visualization of FRAP-like activity in several nonrodent species is discussed with reference to previous work indicating its presence only in mouse and rat. Technical factors are considered that limit the applicability of the lead-ion histochemical method in demonstration of FRAP and in efforts at functional characterization of the enzyme, especially in light of its ability to hydrolyze a broad spectrum of substrates over a wide pH range. Alternative interpretations of the expression of acid phosphatase activity in a select class of small sensory ganglion cells are suggested, including several possible non-synaptic roles of FRAP in the peripheral nervous system.

Lectin and neuropeptide labeling of separate populations of dorsal root ganglion neurons and associated "nociceptor" thin axons in rat testis and cornea whole-mount preparations

As part of a program to explore patterns of innervation by nociceptor-related thin sensory axons in a variety of peripheral regions, we have labeled calcitonin gene-related peptide immunoreactive (CGRP-IR) nerve fibers in whole mounts of rat testicular tunica vasculosa and cornea. Efforts were undertaken to visualize the numerically significant fluoride-resistant acid phosphatase (FRAP)-containing axon population, whose peripheral endings have heretofore remained undemonstrable due to technical limitations of currently available acid phosphatase methods. Various histochemical markers that colocalize with FRAP in dorsal root ganglion (DRG) and spinal cord were examined, and a plant lectin, Griffonia simplicifolia I-B4, has been identified that not only selectively labels FRAP(+) sensory ganglion cells and central terminals in spinal cord, but also differentially stains a large number of thin axons in testicular and corneal whole mounts. Slender lectin-labeled fibers are abundant in cornea, and are distributed throughout tunica vasculosa preparations unrelated to blood vessels. CGRP-IR axons, in contrast, maintain close adherence to vascular patterns and are more coarse and varicose in appearance. Lectin staining therefore provides the first practical and specific method for visualization of peripheral FRAP(+) axons consisting principally of sensory C fibers but possibly including a small number of unmyelinated autonomic axons. It should now be feasible, using individual whole-mount preparations from various peripheral nociceptor-innervated tissues, to examine the distributions of both peptidergic and FRAP(+) fibers, which together comprise the vast majority of thin sensory axons. It may then be possible to correlate the observed anatomical patterns with knowledge regarding properties of corresponding physiologically characterized receptive fields.

Observations on electrophysiologically characterized receptive fields of thin testicular afferent axons: a preliminary note on the analysis of fine structural specializations of polymodal receptors

The sparse distribution of thin, principally unmyelinated sensory axons confined largely to the planar tunica vasculosa of the testis provides a suitable model for examining the fine structure of electrophysiologically characterized nerve fiber terminals. The marked sites of polymodal receptors of canine testis using the in vitro preparation devised by Kumazawa et al. (1987) were examined in serial sections traced to the terminal with the electron microscope, revealing the first micrographs of a characterized polymodal receptor ending. The inferred role of these terminals in nociception, their organelle content, and the problems encountered in interpreting our initial findings are considered in the context of the variety of morphological patterns and functional roles of thin sensory axons.

Localization of specific binding sites for atrial natriuretic factor in the central nervous system of rat, guinea pig, cat and human

Specific, high-affinity binding sites for atrial natriuretic factor (ANF) were identified and localized in the rat and guinea pig central nervous system (CNS), the cat brainstem, and the rat, guinea pig, cat and human spinal cord using quantitative autoradiographic techniques. The radioligands tested were rat 125I-ANF(1-28) in guinea pig, rat, cat and human tissues, human 125I-ANF in rat and human, and rat [3H]atriopeptin III in rat. All 3 radioligands labeled essentially the same structures in the brain and spinal cord of all species in which they were tested. In guinea pig very high concentrations of ANF binding sites were observed in the olfactory bulb, lateral olfactory tract and the granule cell layer of the cerebellum, high concentrations were observed in the fasciculus retroflexus, interpeduncular nucleus and subfornical organ. Moderate concentrations were observed in the nucleus accumbens, dorsomedial and suprachiasmatic hypothalamic nuclei, paraventricular thalamic nuclei, primary olfactory cortex and the subcommissural organ. High concentrations of ANF binding sites were also observed in the choroid plexus and the leptomeninges. Low concentrations were observed in the pineal gland. In the rat the same structures were labeled as in the guinea pig except that suprachiasmatic and dorsomedial hypothalamic nuclei, paraventricular thalamus and cerebellum were unlabeled. In the lower brainstem of the cat and all levels of the rat, guinea pig, cat and human spinal cord, the only site where specific binding was observed was in the pia/arachnoid. These findings suggest that ANF binding sites constitute several functional classes in the CNS as well as in a variety of other tissues. Outside the blood-brain barrier binding sites are prominent in glandular tissues implicated in the production of hormones involved in fluid and electrolyte balance, e.g. adrenal glomerulosa, neurohypophysis and subfornical organ, unstratified epithelia involved in ion gradient exchange, e.g. renal glomerulus, ciliary body, choroid plexus and pia mater; crossing the blood-brain barrier are sites in the anterior hypothalamus, e.g. organum vasculosum, regions of the brain parenchyma associated with angiotensin II binding sites, e.g. dorsomedial nucleus of hypothalamus, some of which may be occupied by brain rather than cardiac synthesized ANF, regions of brain lacking an obvious role in fluid and ion exchange or regulation, e.g. cerebellum, although association with K+,Na+-ATPase in guinea pig cerebellum may be a relevant clue and brain regions possibly implicated in an integrative and/or indirect regulatory role in fluid and electrolyte balance.(ABSTRACT TRUNCATED AT 400 WORDS)

An interpretation of dental innervation based upon the pattern of calcitonin gene-related peptide (CGRP)-immunoreactive thin sensory axons

Calcitonin gene-related peptide (CGRP) is a recently characterized neuroactive substance that is expressed in a large proportion of small- to medium-diameter sensory ganglion neurons whose central terminals lie in the superficial spinal and medullary dorsal horn. This restricted distribution within the peripheral nervous system suggests a prominent role for the peptide in nociceptive processing. The mammalian tooth pulp, which receives a relatively homogeneous afferent input from thin (putative nociceptive) fibers originating from this subpopulation of trigeminal ganglion cells, thus affords an ideal target zone in which to examine peripheral nociceptive mechanisms. The large percentage of these neurons displaying CGRP-like immunoreactivity (CGRP-LI) furthermore provides a valuable tool to study its thin-fiber afferent innervation. CGRP-LI has been localized within intact, decalcified specimens of rat, cat, monkey, and human teeth and associated dental structures. A remarkably robust CGRP-LI innervation of molar pulp and dentin was revealed in all species, with fibers coursing both in fascicles and individually, in variable relation to blood vessels and pulpal stroma. Our methods enabled tracing of a large number of axons through Raschkow's plexus and odontoblast layer into dentinal tubules. Paralleling anterograde axonal transport studies, a greater share of fibers was found in coronal vis-à-vis radicular dentin. In the rat, this fiber pattern stood in contrast both to incisor dentin, which appeared devoid of CGRP-LI, and to the abundant labeled axons in gingiva and periodontal tissues. Surgical deafferentation of rat mandible resulted in widespread depletion of CGRP-LI, while superior cervical ganglionectomy was without effect, confirming the sensory nature of the CGRP-LI fibers. Neonatal capsaicin treatment greatly attenuated the immunostaining, providing evidence for CGRP-LI localization in chemosensitive unmyelinated afferents. The great density of CGRP-LI axons demonstrated is considered in contrast to the restricted range and extent of sensory stimuli to which teeth are presumably subjected, and in relation to the diverse ongoing trophic, regulatory, and reparative processes in tooth structures. It is therefore suggested that these fibers may be subserving prominent efferent roles in dental pulp not directly related to nociception.

Peptidergic nociceptive axon visualization in whole-mount preparations of cornea and tympanic membrane in rat

A whole-mount preparation is described for visualizing unmyelinated peptide immunoreactive axons in two specialized tissues, thin enough for tracing axons to their terminal knobs. These tissues, the cornea and the mucosal surface of the tympanic membrane, are known to possess specialized nociceptor innervation and can be used for selecting sensory endings labeled by peroxidase reaction product and embedded in plastic for more detailed analysis. Rat calcitonin gene-related peptide antibody proved a particularly robust primary antibody found in a substantial proportion of sensory unmyelinated axons in a variety of fixation and preparative conditions.

Localization of specific binding sites for atrial natriuretic factor in peripheral tissues of the guinea pig, rat, and human

Specific, high affinity atrial natriuretic factor (ANF) binding sites were identified and localized by autoradiographic techniques in peripheral tissues of the guinea pig, rat, and human. In the guinea pig kidney, high concentrations of ANF binding sites were located in the glomerular apparatus, outer medulla, and small renal arteries. Other peripheral tissues containing ANF binding sites included the zona glomerulosa of the adrenal cortex, the smooth muscle layer of the aorta and gallbladder, the lung parenchyma, the posterior lobe of the pituitary, the ciliary body of the eye, and the leptomeninges and choroid plexus of the brain. The distribution of ANF binding sites in the rat and human kidney was nearly identical to those seen in the guinea pig kidney; high concentrations were present in the glomerular apparatus, outer medulla, and small renal arteries. These results are consistent with earlier physiological and pharmacological studies that suggested that ANF plays a functional role in the regulation of extracellular fluid volume and blood pressure. There appears to be little species variation in the location and concentration of renal ANF binding sites, suggesting that, at least in the kidney, the results in experimental animals are relevant to the actions of ANF in humans. The finding that ANF binding sites were stable and present in high concentrations in human postmortem kidneys further suggests that these tissues may be amenable to testing for the involvement of ANF receptor dysfunction in diseases such as hypertension and congestive heart failure.

Projections of the rat trigeminal sensory nuclear complex demonstrated by multiple fluorescent dye retrograde transport

The fluorescent dyes True Blue, Fast Blue, Nuclear Yellow and SITS were used to examine the connections of the rat brainstem sensory trigeminal nuclear complex (nV). Particular attention was paid to the following questions: do individual trigeminal neurons project to multiple targets via axon collaterals; and do primary afferent inputs to the various regions of nV arise from individual cells? Pairs of injections, using contrasting dyes, were made into the following target area combinations: ventrobasal thalamus-ipsilateral superior colliculus, cerebellum-contralateral thalamus, nucleus principalis of nV-contralateral thalamus, and nucleus principalis of nV-subnucleus caudalis of spinal nV. In general, numerous neurons throughout all subdivisions of nV and within the trigeminal ganglion were labeled by a single dye following the injections. In addition, many cells in a similar distribution were found to be doubly-labeled following such injection combination. These data demonstrate the existence of significant subpopulations of first- and second-order neurons that project to multiple targets via divergent axonal ramifications throughout the rat sensory trigeminal system.

The response of single guard and down hair mechanoreceptors to moving air-jet stimulation

The response properties of single guard (G) and down (D) hair afferent nerve fibers innervating the hairy skin of the hindlimb were studied in acute barbiturate-anesthetized cats. The purpose of the study was to identify and analyze the relative contribution of those stimulus features determining the discharge patterns evoked in single afferents by a fine air-jet stimulus moving across the skin and varying in force, velocity, position, direction and orientation. The response of single G hair afferents to moving air-jet stimuli reveals that the responsiveness of each fiber to stimuli with arbitrary orientation, direction and position within the receptive field (RF) displays an optimum velocity sensitivity which is not predictable from punctate data. Although the response pattern is remarkably consistent for each moving stimulus condition, there are significant differences in response as a function of stimulus orientation, direction and velocity. RF 'maps' constructed from the responses evoked as the air-jet traverses the skin reveal multiple zones of high and low sensitivity. The distribution of sensitive zones is remarkably consistent for maps constructed with stimuli varying in orientation, direction and velocity. It is apparent that the principal determinant of the response for a given stimulus traverse is the spatial distribution of sensitive spots throughout the RF. Although noticeably more uniform in sensitivity, the RFs of D hair afferents demonstrate similar properties. These findings indicate that G and D hair afferent nerve fibers respond more vigorously to moving stimuli than to stationary displacement and display complex RF inhomogeneities which must be taken into account for the study of central neuronal information processing and feature extraction.

Excitation of dorsal column nucleus neurons by air-jet moving across the skin

Single unit recordings from dorsal column neurons were made during application of mechanical somatic stimuli moving at controlled velocities across the neuron's receptive field. The neurons responded in stereotypic patterns which changed with altered stimulus parameters of velocity, direction and intensity. Spatial analysis of the response patterns indicates that the neurons generate action potentials when the stimulus probe activated particular discrete locations within the receptive field.