Central regulation of sympathetic ganglia development: heterogeneous response of paravertebral, prevertebral, and terminal ganglia

These studies expand previous observations regarding the central control of neuronal maturation and indicate that paravertebral, prevertebral, and terminal ganglia are all under central influences, but in varying degrees. These variations are probably related to the relative contributions that central pathways exert on specific peripheral neuronal populations during growth and development as well as the various roles of more peripheral developmental modulators such as target organs and hormones, especially in the case of the HG. It is apparent, therefore, that during development central injury may result in heterogeneous deficits depending on the unique intrinsic and extrinsic environment that each ganglion population shares.

Effect of buthionine sulfoximine, a synthesis inhibitor of the antioxidant glutathione, on the murine nigrostriatal neurons

This study analyzed the effects of acute systemic treatment with buthionine sulfoximine (BSO), a synthesis inhibitor of the antioxidant reduced glutathione (GSH), on dopaminergic neurons of the murine nigrostriatal pathway. Part 1 of the study established a dose-response curve and the temporal pattern of GSH loss and recovery in the substantia nigra and striatum following acute BSO treatment. Part 2 of the study determined the effect of acute BSO treatment on the morphology and biochemistry of nigrostriatal neurons. We found that decreases in GSH levels had profound morphological effects, including decreased catecholamine fluorescence per cell, increased levels of lipid peroxidation and lipofuscin accumulation, and increased numbers of dystrophic axons in dopaminergic neurons of the nigrostriatal pathway. However, no measurable effects were observed in biochemical levels of either dopamine or its metabolites. These changes mimic those that have been reported to occur in the nigrostriatal system of rodents with advancing age. Our data suggest that reduction of GSH via BSO treatment results in the same types of nigrostriatal degenerative effects that occur during the aging process and consequently is a good model system for examining the role of GSH in protecting this area of the brain against the harmful effects of age-related oxidative stress.

Advances in Alzheimer's disease

Investigations linking this disorder to numerous factors, such as neurotransmitters and apolipoprotein E, are leading to future drug therapy. Current patient care must be focused on finding and alleviating the causes of immediate behavioral concerns.

Calbindin D28k mRNA in hippocampus, superior temporal gyrus and cerebellum: comparison between control and Alzheimer disease subjects

To further investigate the role of calbindin D28k in Alzheimer's disease (AD); hippocampus, superior temporal gyrus and cerebellum from control and AD cases were examined by quantitative in situ hybridization. We report here a decrease in CaBD28k mRNA in the CA2 region of AD hippocampus compared to control subjects. There were no significant differences between AD and control subjects in the other regions studied.

Glucocorticoid receptor mRNA in Alzheimer's diseased hippocampus

Hypothalamic-pituitary-adrenal (HPA) axis dysfunction is a common finding in Alzheimer's dementia. Since there is a loss of hippocampal corticosteroid receptors in animal models of aging, and since hippocampal cell loss occurs in Alzheimer's disease (AD), it has been suggested that a loss of hippocampal glucocorticoid receptors (GR) may underlie some aspects of HPA axis dysfunction in patients with AD. Levels of corticosteroid receptor protein are not reliably determined in postmortem human brain due to rapid lability. In contrast, levels of mRNA coding for GR are stable in postmortem tissue. We report here initial observations from in situ hybridization experiments which indicate that regional levels of glucocorticoid receptor mRNA in hippocampus, as determined by film autoradiography, are significantly higher in AD hippocampus than in controls. While neuronal levels of GR mRNA in AD, revealed by emulsion autoradiography, were equal in control and AD tissue. Taken together these results suggest that adrenal dysfunction in AD may relate to defects in receptor function rather than corticosteroid receptor loss in the hippocampus.

Current diagnostic guidelines for Alzheimer's disease

The pointers outlined recommend specific steps for the neurologic examination, assessment instruments for detecting physical and cognitive dysfunction and mood alteration, and relevant laboratory tests. When to use imaging studies is highlighted.

Postmortem stability of mRNA for glucocorticoid and mineralocorticoid receptor in rodent brain

The relative postmortem stability of the mRNA's for glucocorticoid (GR) and mineralocorticoid (MR) receptor in rodent brain was determined using semi-quantitative in situ hybridization (ISH). Rats were killed by CO2 asphyxiation and their brains removed immediately (0 h) or following 12 h or 24 h delays. Specific hybridization of GR and MR anti-sense [35S]RNA-probe to tissue mRNA encoding these receptors was detected using film and emulsion autoradiography. The most intense labeling for GR mRNA was in the dentate gyrus followed by the CA1 hippocampal region. Lower, but still detectable signal, was apparent over CA3-CA4 pyramidal cell regions. MR mRNA was detected throughout the CA1-4 pyramidal cell fields of the hippocampus and the granular cells of the dentate gyrus. Film images demonstrated that even in the 24 h postmortem delay group intense specific signal was present in sections hybridized with both anti-sense GR and MR probes, although there was some diminution in signal intensity in cortical areas at this later postmortem delay. These initial experiments with rat brain demonstrate that the mRNA's for both GR and MR, as detected with ISH, are stable for up to 24 h following death.

End-stage Alzheimer's disease. Glasgow Coma Scale and the neurologic examination

OBJECTIVE

To characterize the cognitive and neurologic features of patients with end-stage Alzheimer's disease using a standard neurologic examination and the Glasgow Coma Scale.

DESIGN

Case series.

SETTING

Local community nursing homes.

PATIENTS

Forty patients with Alzheimer's disease were drawn from previously enrolled subjects in the Rochester Alzheimer's Disease Project with Clinical Dementia Rating scores of 3, 4, or 5.

MAIN OUTCOME MEASURES

Scores on the Glasgow Coma Scale and cognitive screening examinations and the prevalence of neurologic manifestations such as primitive reflexes and extrapyramidal signs were compared across the Clinical Dementia Rating groups.

RESULTS

When compared with patients in the Clinical Dementia Rating stages 3 and 4, patients with a stage 5 scored significantly lower on the Glasgow Coma Scale, with the discriminating subscales being verbal and motor responses. Primitive reflexes, myoclonus, and dyskinesia were increasingly prevalent in the more terminal stages. Cognitive screening assessments did not discriminate between groups.

CONCLUSIONS

Rudimentary neurologic functions can be readily assessed and, when viewed together with the Glasgow Coma Scale, may circumvent the "floor effect" frequently encountered when using the currently available cognitive and functional scales and, thereby, better define patients with end-stage Alzheimer's disease.

Characterization of brain samples in studies of aging, Alzheimer's, and other neurodegenerative diseases

We review current understanding of the clinical and pathologic information needed for the determination of optimal brain tissue samples for the conduct of studies of Alzheimer's disease (AD). Characteristics that may distinguish AD from other dementing disorders are discussed. Selected considerations in the conduct of basic neurobiological studies are also outlined. Although the 28 NIA-funded Alzheimer's Centers can provide excellent clinical and neuropathological data, studies conducted outside these centers should also strive to gather the information suggested here. Clinical and neuropathological data should be used not only to classify subjects as control or AD, but also as variables that may significantly contribute to the analysis of neurobiological data obtained in the laboratory.

Increased levels of truncated nerve growth factor receptor in urine of mildly demented patients with Alzheimer's disease

OBJECTIVE

In Alzheimer's disease, cholinergic basal forebrain neurons, which have receptors for nerve growth factor (NGF), degenerate, while NGF receptors increase in some areas of the neocortex. Levels of the truncated, extracellular portion of the NGF receptor (NGF-Rt) are elevated in urine of patients with peripheral neuropathies and in animals with peripheral-nerve injury, but it has not been determined whether urine levels of NGF-Rt are altered by the presence and/or progression of dementia-related neuropathologic changes in patients with Alzheimer's disease. In this study, we developed an enzyme-linked immunosorbent assay to determine whether urine levels of NGF-Rt are altered in patients with Alzheimer's disease.

DESIGN

Survey of urine NGF-Rt levels in neurologically normal (n = 19), mildly demented (n = 31), and moderately to severely demented (n = 31) patients.

SETTING

Subjects were participants in the Rochester Alzheimer's Disease Project and mildly demented patients about to begin a clinical drug study.

PATIENTS

All patients met established criteria for a clinical diagnosis of probable Alzheimer's disease. Aged, nondemented, neurologically normal controls were selected from the families of the demented subjects.

RESULTS

Urine NGF-Rt levels were substantially elevated in mildly demented patients relative to those of nondemented controls.

CONCLUSIONS

These results suggest that an enzyme-linked immunosorbent assay on urine samples may provide an antemortem measure of dementia-related neuropathologic changes, but further study is needed to determine the source and potential clinical utility of increased NGF-Rt levels in urine of mildly demented patients.

Acetylcholinesterase staining and choline acetyltransferase activity in the young adult rat spleen: lack of evidence for cholinergic innervation

Acetylcholinesterase (AChE) staining in spleens from young adult Sprague-Dawley rats was examined following several denervation paradigms to determine the source of splenic AChE+ nerve fibers. In spleens from all control groups, AChE+ neural-like profiles were present along the vasculature and in the trabeculae. AChE+ reactivity also was present in lymphoid and reticular cells in the spleen, and in neuronal cell bodies in the superior mesenteric-coeliac ganglion (SM-CG). Neurochemical analysis revealed no significant choline acetyltransferase activity in spleens from control animals. Surgical removal of the SM-CG resulted in a total loss of both noradrenergic (NA) and AChE+ nerve profiles, as well as a loss of AChE staining in nonneural compartment in the spleen. On Days 1 and 3 after treatment, chemical sympathectomy with 6-hydroxydopamine also resulted in a loss of both NA and AChE nerve profiles in the spleen, except for a few resistant fibers in the hilar region. AChE reactivity in nonneural compartments also was diminished in chemically denervated regions of the spleen. AChE staining in both neural and nonneural profiles progressively increased from 10 to 56 days after chemical sympathectomy, with a time course and distribution pattern similar to NA fibers reinnervating the spleen. AChE+ staining was preserved following bilateral vagal nerve transection. The miniscule splenic levels of choline acetyltransferase suggest that at best, only a small density of cholinergic nerves distribute to the rat spleen. Further, what cholinergic innervation is present does not arise from the vagus nerve as suggested in the earlier literature. Collectively, the overlapping distribution of AChE+ and NA nerve profiles in spleen and parallel loss of both population of nerve fibers following surgical and chemical sympathectomy support the presence of AChE in NA nerves colocalized with norepinephrine, and thus make AChE+ staining an inappropriate marker for cholinergic innervation in the rat spleen.

Clinicopathologic correlates in Alzheimer disease: assessment of clinical and pathologic diagnostic criteria

The neuropathologic findings from a group of 123 patients who have come to autopsy from the Rochester Alzheimer Disease Project (RADP) are presented. Among these 123 cases, there were 94 demented subjects who met the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer Disease and Related Disorders Association (NINCDS-ADRDA) clinical criteria for the diagnosis of "probable Alzheimer disease," and 29 normal elderly controls. Autopsy confirmation of Alzheimer disease (AD) was based on the age-graded National Institutes of Health (NIH) consensus conference pathologic criteria. Using the NINCDS-ADRDA clinical criteria and the NIH pathologic criteria, the diagnostic accuracy was 88%, the sensitivity was 98%, and the specificity was 69%. Additional strict clinical and pathologic criteria developed by the RADP were applied in the final review of these cases to exclude all confounding causes of dementia, including cerebral infarcts. After applying these additional criteria, a subset of 62 cases of "pure" AD and "pure" control subjects was identified for a more detailed examination of neuritic plaques (NP) and neurons containing neurofibrillary tangles (NFT). The NP and NFT were counted in three subfields of hippocampus and two areas of association neocortex. The density of diffuse plaques (plaques lacking dystrophic neurites) was estimated on a semiquantitative basis. Results show that the AD patients and control groups could be distinguished from each other easily on the basis of mean NP and NFT counts, but there was sufficient overlap in the counts to present difficulty in diagnosing any individual case. Abundant diffuse plaque involvement and NFT in the neocortex were, however, seen only in AD cases.

Molecular aspects of the regulation of tyrosine hydroxylase by testosterone

Previous studies have demonstrated that the sympathetic hypogastric ganglia (HG) are dependent upon the continued presence of testosterone for normal development and maintenance of tyrosine hydroxylase (TH) activity. The regulation of TH by testosterone has been examined further to determine whether the reduction in TH activity following castration is associated with changes in levels of TH protein and mRNA. TH protein was measured by immunotitration of HG homogenates using a TH-specific antibody, and TH-specific mRNA was detected by hybridization of dot blots of total RNA isolated from HG with a cDNA probe coding for TH. The results show that tyrosine hydroxylase activity, protein and mRNA are coordinately reduced in a graded fashion at 1, 2 and 4 weeks following castration. Testosterone replacement therapy immediately following castration prevents the decrease in TH levels. The results indicate that gonadal steroids regulate the biosynthesis of TH in the HG. Testosterone may control TH either directly by interacting with neurons of the HG, or indirectly by altering levels of trophic factors in the target tissues.

Traumatic brain injuries: predictive usefulness of CT

The computed tomographic (CT) scans from 72 patients with traumatic brain injury were reviewed to determined whether a specific type, location, or size of lesion correlated with changes in neurologic function (assessed with the Glasgow Coma Scale [GCS]), patient outcome (assessed with the Glasgow Outcome Scale [GOS]), or catecholamine levels. The lesions were classified as focal or diffuse. GOS changed as a function of lesions size (P = .00004) in the 48 patients with focal hemorrhages, regardless of whether the lesions were intra- or extraaxial, and in the 19 patients with normal CT scans. Patients with lesions larger than 4,100 mm3 had a twofold greater risk of a poor outcome than patients with smaller lesions (100% vs 50%). Patients with normal CT scans were significantly more likely to have mild neurological dysfunction or none than patients with abnormal CT scans (P = .03), but lesion location, skull fracture, and pineal shift were not significant predictors of GCS or GOS scores. A positive relationship existed between lesion size and both plasma norepinephrine and epinephrine levels (P less than .02); a significant relationship existed between lesion size and GCS score (P = .02).

Brainstem enkephalinergic projections to spinal autonomic nuclei

The present studies in the rat employed a combined retrograde transport-immunocytochemical technique to determine the origin in the brainstem of enkephalin (Enk) projections to spinal sympathetic nuclei, including the intermediolateralis nucleus, pars principalis (ILp). We found that Enk projections to the ILp nucleus are found in such serotonergic-containing areas as the raphe obscurus; raphe pallidus; gigantocellular reticular nucleus, pars alpha; paragigantocellular lateral nucleus; raphe magnus; and the rostral extension of the raphe magnus nucleus. The adrenergic-containing rostroventrolateral reticular nucleus as well as the noradrenergic-containing areas A5, A7, ventral locus coeruleus, subcoeruleus, and fiber pathway linking the locus coeruleus and A5/A7 send Enk projections to ILp. In the pons, a large contralateral Enk projection to spinal sympathetic nuclei was found medial to the facial nerve and medial to the motor nucleus of the trigeminal nerve. These observations show the existence of a large number of Enk brainstem regions that can influence spinal autonomic centers via descending supraspinal projections.

Effects of intoxication on the catecholamine response to multisystem injury

In patients suffering isolated head trauma, we have previously shown that levels of circulating catecholamines obtained within 48 hours of trauma correlate with the severity of brain injury and predict outcome and that intoxication blunts this response. The effects of alcohol on the increase in catecholamines in systematically injured patients, however, have not been well defined. From 1983 to 1990, 78 patients (74% male; median age 30 years) with blunt head and multisystem injury, who also had alcohol levels measured within 5 hours of injury, were studied. Norepinephrine and epinephrine levels were assayed by a radioenzymatic technique. Injury severity was assessed by the admission Glasgow Coma Scale (GCS) score (4-15; median, 12), the Injury Severity Score (ISS) (13-50; median, 25) and the volume of blood products administered within the first 24 hours (0-14.4 L; median, 0.5 L). The impact of alcohol on the norepinephrine response to injury was analyzed using multiple linear regression models, including polynomial interaction terms. Norepinephrine levels significantly (p less than 0.0001) correlated with the GCS score and ISS. However, alcohol significantly lowered the norepinephrine response to decreasing GCS score (R = 0.49, p less than 0.002) and to increasing ISS (R = 0.51, p less than 0.0006). The blunting of the catecholamine response was most marked in those severely injured. The rise in norepinephrine concentrations seen with increasing volume of blood replacement was not affected by intoxication. An association between injury severity and epinephrine levels was also present, but not as consistently. Epinephrine concentrations rose with falling GCS score and with increasing ISS values, but unlike norepinephrine, there were no apparent effects of alcohol on changes in epinephrine levels. Thus, in patients suffering head and multisystem injury, catecholamine changes reflect the severity of injury using three different scalers. Furthermore, intoxication blunts only the norepinephrine component of this important biologic response.

The amygdala in Alzheimer's disease: neuropathology and Alz 50 immunoreactivity

Patients with Alzheimer's disease (AD) often show emotional, motivational, and memory disturbances which may have morphological substrates that include the amygdaloid complex. Neuropathological studies in other limbic areas have recently been enhanced by immunocytochemical studies with Alz 50 antibody. Therefore, we examined the distribution of Alz 50 immunoreactive (Alz 50-IR) neuritic plaques (NP) and neurofibrillary tangles (NFT) in the amygdala in AD cases, in one aged patient with Down's syndrome, and in controls of similar ages. In all AD cases numerous NP and variable numbers of NFT were observed and a distinctive subregional anatomical distribution of NP and Alz 50-IR neuropil in the amygdala existed, whereas no similar selective topography for NFT or Alz 50-IR neurons was found. A high density of NP was demonstrated in the ventromedial aspects of the basolateral and corticomedial nuclear regions. There was no correlation with the pattern of cholinergic innervation. There was, however, a correspondence between intraamygdaloid- and amygdaloid-hippocampal connections and regions of high NP density. Our findings support the concept that the disease process may occur along anatomically defined pathways, and the amygdala may be a central participant in this process.

Tardive dyskinesia in Alzheimer's disease: clinical features and neuropathologic correlates

Medical record review was conducted on 14 patients with neuropathologically confirmed Alzheimer's disease, all of whom had been treated with antipsychotic medications, to determine the relationship between neuropathology and the development of tardive dyskinesia. Four cases were found to have chart descriptions of hyperkinetic movement disorders consistent with tardive dyskinesia. When the group with tardive dyskinesia was compared to the group without tardive dyskinesia, there were no statistically significant differences regarding gender, age of onset of dementia, duration of dementia, age at death, or duration of antipsychotic treatment. Neuropathologic comparisons revealed greater degenerative changes in the substantia nigra in those patients with tardive dyskinesia. These preliminary observations suggest that patients with Alzheimer's disease and significant coexisting substantia nigra pathologic changes may be at higher risk for developing tardive dyskinesia when treated with antipsychotic medication.

Pisa syndrome without neuroleptic exposure in a patient with dementia of the Alzheimer type

A case of Pisa syndrome in a 60-year-old man with dementia, probably of the Alzheimer type, who had never been exposed to any psychotropic medication is described. He also had some extrapyramidal features and myoclonus. Treatment with amantadine was slightly beneficial. We believe that this report is the first of its kind.

The adrenocortical response to brain injury: correlation with the severity of neurologic dysfunction, effects of intoxication, and patient outcome

To test the hypothesis that cortisol levels reflect the extent of neurologic dysfunction and predict patient outcome, neurologic function and cortisol levels were determined in 120 traumatically brain injured patients who never received glucocorticoid treatment. Their mean age was 29 years and 78% were men. The impact of intoxication was examined in 59 patients who had ethanol levels measured. Ethanol was detectable in 40 patients and greater than or equal to 100 mg/dl in 31. There were significant correlations between the extent of neurologic dysfunction, determined by the Glasgow Coma Score and plasma cortisol concentrations 1 and 4 days postaccident. Cortisol levels were universally elevated on admission and approached normal 7 days later. Multiple linear regression analysis revealed significant effects of circulating ethanol levels on the association between cortisol concentrations and progressively worsening neurologic function, i.e., ethanol reduced the magnitude of the cortisol elevations in a dose dependent manner, abolishing this relationship at levels above 100 mg/dl. Analysis of the relationships between circulating cortisol levels and patient outcome provided a second method for ascertaining the association between injury severity and the magnitude of adrenocortical activation. Admission and day 1 cortisol concentrations were 25 to 40% lower in patients having good recoveries or moderate disabilities than those who remained severely disabled, persistently vegetative or died; serum cortisol values of less than 20 micrograms/dl one day after the accident were more likely to be associated with a good outcome than a poor one (55 vs. 25%, p less than 0.001). The worsening prognosis of patients having higher cortisol values is further reflected in the duration of acute hospitalization of these individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Hormonal regulation of adult sympathetic neurons: the effects of castration on neuropeptide Y, norepinephrine, and tyrosine hydroxylase activity

Previous studies utilizing the hypogastric ganglia (HG) have indicated that gonadal steroids exert organizational and activational effects on noradrenergic biochemistry. Bilateral castration of male rodents at birth prevents the normal maturation of tyrosine hydroxylase (T-OH) activity in the HG; castration during adulthood results in a progressive decline in T-OH activity. Testosterone replacement corrects both the ontogenetic and adult functional alterations in the neurotransmitter-synthesizing enzyme. The present studies in adult male rats extend these previous observations and asked the question whether gonadal steroids regulate the neurotransmitters neuropeptide Y (NPY) and norepinephrine (NE) in the HG. Adult rodents were castrated and ganglia T-OH, NPY, and NE were examined at various time points after surgery. All three indices of sympathetic neuron biochemistry declined following castration, but they exhibited different profiles. It appears that hormones may affect enzyme activity and neurotransmitter pools differently within neurons. Testosterone replacement therapy fully restored T-OH activity, and NPY and NE levels in the HG. These studies extend the activational role of testosterone in regulating sympathetic neuron neurotransmitter and neuropeptide levels as well as neurotransmitter-synthesizing enzymes.

Alcohol intoxication blunts sympatho-adrenal activation following brain injury

In 46 patients experiencing traumatic brain injury, we studied the interactions of alcohol intoxication and severity of neurologic dysfunction on the resulting sympathetic nervous system activation. Sixty percent of the variation in norepinephrine (p less than 0.0001) and more than 50% of the variation in epinephrine (p less than 0.0001) were due to the initial ethanol concentrations and extent of brain injury assessed by the admission Glasgow Coma Score (GCS). As brain function deteriorated plasma cathecholamines rose (p less than 0.0001), but ethanol qualitatively and quantitatively modified this observation. The magnitude of the sympathetic response to worsening neurologic function was progressively diminished in association with increasing ethanol levels, i.e., the inverse relationship of GCS values with both norepinephrine and epinephrine was flattened. In comatose patients (GCS less than 8) increasing ethanol levels was associated with progressively decreasing norepinephrine and epinephrine responses (p less than 0.04), such that catecholamines were reduced by 80 to 90% at ethanol concentrations approaching 400 mg/dl (87.0 mmol/l). However, the impact of ethanol on the degree of sympathetic nervous system activation depended upon the degree of injury; the apparent ethanol suppression was greatest in patients with the most severe neurologic dysfunction (GCS 3 or 4), but it diminished as neurologic function improved. We conclude that the presence of alcohol appears to modify the rise in catecholamine levels following traumatic brain injury in a dose-dependent manner and alters the relationship between neurologic dysfunction and SNS activation. These alterations may have profound effects on patient morbidity in the immediate post-accident period.

Calcitonin gene-related peptide and somatostatin immunoreactivities in the rat lumbar spinal cord: sexually dimorphic aspects

The immunohistochemical distribution of calcitonin gene-related peptide and somatostatin in rat lumbar spinal laminae VII-X was investigated using the peroxidase-antiperoxidase technique. Within L1,2 laminae VII and X, calcitonin gene-related peptide and somatostatin fibers demarcate the location of preganglionic sympathetic neurons in a similar fashion in either sex but somatostatin is distributed in a sexually dimorphic manner in the lumbosacral (L5-S2) spinal cord with the male rat containing more somatostatin fibers and neurons than females. Within the ventral horn (lamina IX), calcitonin gene-related peptide has a sexually dimorphic distribution. Calcitonin gene-related peptide varicose fibers are found within the sexually dimorphic male cremaster nucleus but are virtually absent in the female cremaster nucleus. Calcitonin gene-related peptide varicose fibers are nearly absent in the remainder of the male and female lamina IX: this area includes the other two known sexually dimorphic spinal motonuclei: the dorsomedial and dorsolateral nuclei. Virtually all motoneurons in the lumbosacral spinal cord which are not sexually dimorphic contain calcitonin gene-related peptide. However, calcitonin gene-related peptide containing motoneurons have a heterogeneous distribution within sexually dimorphic nuclei. Calcitonin gene-related peptide containing motoneurons within the male and female cremaster nucleus are extremely rare. Some motoneurons within the male and female dorsomedial and dorsolateral nuclei contain calcitonin gene-related peptide with the female dorsomedial and dorsolateral nuclei containing a greater percentage of calcitonin gene-related peptide-containing motoneurons (c. 50%) than males (c. 20%). Somatostatin fibers are preferentially located in sexually dimorphic nuclei of either sex and are distributed in a sexually dimorphic manner within these nuclei with males containing a greater amount of somatostatin fibers than females. The amount of somatostatin immunoreactivity is most dense in the medial aspect of the dorsolateral nucleus, dense in the dorsomedial nucleus, moderate in the cremaster nucleus, and sparse in the lateral portion of the dorsolateral nucleus. In addition, a small column of motoneurons, between the dorsomedial and dorsolateral nuclei at the L5 level, is outlined by somatostatin fibers in females but is absent in males. Somatostatin containing motoneurons were not observed within the lumbar sexually dimorphic nuclei of either sex.

The ontogeny of substance P- and serotonin-like immunoreactivities in the sexually dimorphic cremaster nucleus of the rat spinal cord

This study investigates the ontogeny of two transmitter systems which innervate the sexually dimorphic cremaster nucleus (CN). Since these transmitter systems arise from separate extra- and intraspinal sources, their ontological sequences differ. In males, substance P (SP) innervates CN motoneurons on postnatal day (P) 0, while serotonin (5-HT) is first observed on P2. SP reaches a mature innervation pattern on P20, while 5-HT maturation is prolonged to P40-60. It is suggested that part of the reason for the differing rates of development of 5-HT and SP within CN is due to the source of the innervating fibers; 5-HT descends from the brainstem while SP is of intraspinal origin. On P6, the SP innervation of the dorsal processes of the male CN is so advanced that the spinal cord may be 'sexed' according to the male presence, or the female 'absence', of this SP pattern. In developing and adult females, the 5-HT innervation of the CN is greater than the SP innervation. In addition, the 5-HT and SP innervation of the female CN is greater than the surrounding motor columns. Compared to surrounding ventral gray horn motor nuclei, the CN receives a slightly delayed SP and 5-HT innervation and this may be a reflection of the postnatal formation of the cremaster muscle.

Parasympathetic nerves in penile erectile tissue of the rat contain choline acetyltransferase

Choline acetyltransferase (ChAT), a biochemical marker of cholinergic neurons, was measured in the erectile tissue of intact rats and in rats in which postganglionic fibers from the pelvic plexus were interrupted. ChAT activity in the denervated erectile tissue fell by 56% compared to control tissues. Acetylcholinesterase positive (AChE+) nerves also fell by about 48%. Penile neurons distal to the lesion probably account for the residual ChAT activity and remaining AChE+ nerve fibers in erectile tissue. These results indicate that acetylcholine is an important neurotransmitter in the regulation of penile erection.

Organizational role of testosterone on the biochemical and morphological development of the hypogastric ganglion

Previous reports have demonstrated that after postnatal day 10 testosterone influences hypogastric ganglion (HG) development by 'activating' morphological and biochemical indices. We now report an 'organizational' influence on the developing HG during the first 10 postnatal days. To investigate the organizational effects of testosterone, male rats were castrated within 12 h of birth. Testosterone replacement therapy initiated following castration maintained the normal number of neurons in the HG. Conversely, delayed replacement therapy starting at day 10 or vehicle treatment only, resulted in a significant decrease in neuron number. Castration also produced a significant decrease in somal and nuclear cross-sectional areas. Testosterone replacement, whether initiated immediately or if delayed until day 10, restored somal and nuclear cross-sectional areas to normal. Tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT) activities were sensitive to both testosterone dosage and the time of administration. Testosterone decanoate administered subsequent to castration was not able to completely reverse the enzyme activity deficits, while delayed replacement therapy was even less effective in restoring enzyme activities. In contrast, higher doses of testosterone completely reversed enzyme activity deficits, and in fact produced a significant increase in TH activity. Again, delayed testosterone replacement did not fully restore deficits in enzyme activity. In summary, the hormonal environment during the first 10 days of life is critical for the organization of HG cell number; in contrast, nuclear and cell size appear to be dependent on testosterone for activation. TH and ChAT activities also appear to be organized during this dose- and time-dependent developmental period.

Target regulation of the serotonin and substance P innervation of the sexually dimorphic cremaster nucleus

The effects of perinatal castrations on the serotonin (5-HT) and substance P (SP) innervation patterns of the adult male cremaster nucleus (CN) were examined in Sprague-Dawley rats. These investigations reveal that day-of-birth bilateral castration precludes cremaster muscle formation, significantly reduces CN motoneuron number, and dramatically reduces the 5-HT and SP innervation of the adult male CN. Day-of-birth castration reduces the adult CN SP innervation pattern to a greater degree than the 5-HT pattern and this may be attributed to a substantial loss of primary afferent information to the dorsal horn of the spinal cord. Furthermore, day-of-birth unilateral castration causes an ipsilateral reduction in the adult 5-HT and SP immunostaining patterns. This may be correlated with the failure of the ipsilateral cremaster muscle to form with a subsequent ipsilateral reduction of CN motoneuron number. On the contralateral side the intact testis is accompanied by normal cremaster muscle gross morphology, CN motoneuron number, and CN immunostaining. Together these observations suggest that the sexually dimorphic 5-HT and SP innervation of the male CN is predominantly under target control vs androgen control. Castration during adulthood does not alter the 5-HT and SP innervation patterns of CN; thus, a time-dependent period, probably initiated by cremaster muscle formation, underlies these target organ regulatory effects.

Hypogastric ganglion perinatal development: evidence for androgen specificity via androgen receptors

The hypogastric ganglion (HG) has previously been shown to be sensitive to both the organizational and activational influences of testosterone. The current investigations examined whether testosterone exerts similar effects prenatally, whether these events are specifically controlled by androgen, and whether androgens might directly masculinize the HG. Prenatal treatment with an anti-androgen, flutamide, resulted in significant decreases in the adult levels of tyrosine hydroxylase (TH) activity, an index of postsynaptic noradrenergic ontogeny, and choline acetyltransferase (ChAT) activity, a marker for presynaptic terminal formation. In addition, testosterone propionate and dihydrotestosterone benzoate reversed the effects of neonatal castration on the development of TH and ChAT activities. In contrast estradiol benzoate was unable to restore enzyme activities. To determine whether the above observations might be produced by direct effects on the HG, androgen cytosol receptor characteristics were studied. Competition and saturation analyses demonstrate that the affinity and specificity of the androgen cytosol receptor in the HG are similar to that displayed in the pituitary, which has previously been shown to contain androgen receptors. These results suggest that the adult levels of TH and ChAT activities are organized during prenatal and early postnatal development. In addition, the organization of the HG appears to be androgen specific. The presence of cytosol androgen receptors suggests that the organizational effects of androgens are possibly induced by a direct mechanism.

Postnatal ontogeny of enkephalin fibers in spinal sympathetic nuclei

The postnatal distribution of enkephalin (Enk) fibers is described in preganglionic containing sympathetic nuclei in the rat thoracolumbar spinal cord. In high thoracic spinal cord, at birth, Enk fibers are present in moderate numbers in the intermediolateralis nucleus, pars principalis (ILp), and nucleus intercalatus spinalis (IC). Enkephalin fibers first appear in the dorsal commissural nucleus (dcn) on postnatal day 2. Postnatal day 6 represents a pivotal timepoint when the basic Enk innervation pattern is established. From postnatal day 11 through day 20 there is a gradual accumulation of Enk fibers within each of the sympathetic nuclei such that the density and distribution of immunoreactive fibers approaches the adult appearance by postnatal day 20. An adult pattern is achieved by postnatal day 30. There is a rostral-caudal gradient in the developmental appearance of Enk fibers in sympathetic nuclei such that the ILp nucleus contains Enk fibers on postnatal day 0 in the high thoracic spinal levels compared to postnatal day 6 in low thoracic-high lumbar spinal levels. Examination of the location of Enk fibers during ontogeny highlighted several additional features of the distribution of Enk fibers in the adult animal. Enkephalin fibers delineate two subdivisions of the IC nucleus; a thin dense core of Enk fibers contained within a broader band of moderate numbers of Enk fibers. We also report variations in the general overall pattern of the Enk fiber distribution in high thoracic, middle thoracic, and lwo thoracic-high lumbar spinal cord levels.

Androgen-specific critical periods for the organization of the major pelvic ganglion

Previous studies indicate that the major pelvic ganglion (PG) is dependent on testosterone for normal development. Tyrosine hydroxylase (T-OH), DOPA decarboxylase, and choline acetyltransferase (CAT) activities are significantly reduced by postnatal castration on day 10-11, while testosterone replacement therapy reversed all developmental enzyme activity deficits (Melvin and Hamill, 1987). In the present studies castration on the day of birth combined with various testosterone-replacement paradigms produced effects demonstrating that the PG is sensitive to testosterone dosage and time of administration during early postnatal development. Gonadal hormone replacement experiments show that the androgens testosterone and dihydrotestosterone were effective in restoring T-OH and CAT activity deficits produced by neonatal castration. Estrogen therapy reversed the deficits in CAT activity, but was ineffective in reversing the alterations in T-OH activity. Treatment of pregnant dams with the anti-androgen flutamide altered the ontogeny of T-OH and CAT activities in pups despite replacement therapy on the day of birth. Thus, androgen-critical periods exist prenatally as well as postnatally. These studies suggest that the organization of PG development is critically dependent on both the time of exposure and dose of testosterone. Prenatal and postnatal critical periods appear to exist. In addition, the lack of an effect of estradiol on tyrosine hydroxylase activity suggests that androgens are specifically responsible for organizing the noradrenergic development of the PG.

Immunohistochemical distribution of serotonin in spinal autonomic nuclei: I. Fiber patterns in the adult rat

The differential distribution of serotonin (5HT) fibers in spinal laminae VII and X is described for the adult rat. The results indicate that descending 5HT fibers preferentially innervate those regions of lamina VII that contain sympathetic and parasympathetic neurons. In lamina X, especially the dorsal commissural nucleus, large numbers of 5HT fibers are observed throughout the spinal cord. Moreover, sympathetic nuclei are more richly innervated with 5HT than the spinal parasympathetic nuclei. Spinal cord hemisections reveal that spinal autonomic nuclei are differentially innervated: ipsilateral serotoninergic projections to the intermediolateral cell column are preferentially interrupted. In addition, a large crossed 5HT projection exists throughout the length of the spinal cord that decussates five to six spinal segments rostral to its termination. Both crossed and uncrossed 5HT fibers span many spinal segments and have large numbers of collaterals. Spinal cord transections show that the vast majority of spinal 5HT descends from the brainstem but that some 5HT fibers are of intrinsic origin.

Immunohistochemical distribution of serotonin in spinal autonomic nuclei: II. Early and late postnatal ontogeny in the rat

These studies reveal that the postnatal ontogeny of serotonin (5HT) in the sympathetic nuclei of the rat spinal cord is protracted; the adult complement of 5HT-immunoreactive fibers is not achieved until at least 60 days of age. As descending serotonin fibers innervate and demarcate the distribution of preganglionic sympathetic nuclei, rostral-caudal and temporal gradients exist. Additionally, a heterogeneous segmental 5HT ontogenetic pattern is observed in sympathetic nuclei. Most serotonin fibers in laminae VII and X are unorganized at birth except for some sympathetic nuclei in high thoracic regions where the 5HT sympathetic pattern is being initiated. By postnatal day 6 the framework of the 5HT pattern is established in all sympathetic nuclei, and by postnatal day 16 a pattern is formed, which develops into the compact adult state by postnatal day 60. The protracted period of sympathetic 5HT development corresponds with the length of time it takes for the autonomic nervous system to mature. In addition, 5HT intraspinal cell bodies are observed at all time points examined, except for the day of birth, and are found in the same regions as adult 5HT neurons, i.e., dorsal or lateral to the central canal in laminae VII and X and in all spinal segments except cervical levels. Many of the 5HT neurons are pericanalicular and bipolar in appearance. Multipolar 5HT neurons are first observed on postnatal day 45.

The postnatal ontogeny of substance P-immunoreactive fibers in the sympathetic preganglionic nuclei of the rat

The ontogeny of substance P (SP)-containing fibers and puncta is described in laminae VII and X of the rat thoracolumbar spinal cord from the day of birth until postnatal day (P) 60. As SP fibers and puncta innervate and demarcate the distribution of preganglionic sympathetic nuclei, strong temporal and weak rostrocaudal ontogenetic gradients exist. Additionally, a heterogeneous segmental SP ontogenetic pattern is observed in sympathetic nuclei. On the day of birth, SP fibers are present in an unorganized fashion in sympathetic nuclei with the exception of the nucleus intercalatus which is clearly outlined. From P0 to P4 SP fibers and puncta are established along a 'ladder-like' pattern and from P6 to P15 SP fibers and puncta steadily accumulate in sympathetic nuclei at all spinal levels. By P15 the nuclei intermediolateralis, pars principalis and funicularis, and the nucleus intercalatus are clearly outlined by SP immunoreactivity while the central autonomic region (lamina X) contains heterogeneous bands of SP immunoreactivity. From P20 to P30, SP fibers and puncta accumulate in each autonomic nucleus and longitudinal SP connections form between each adjacent nucleus intermediolateralis pars principalis. Along the spinal midline the nucleus intercalatus pars paraependymalis and the dorsal commissural nucleus emerge from the central autonomic region as separate SP-innervated nuclei. On P40 a period of reorganization takes place so that SP fibers within sympathetic nuclei become more diffuse and the nucleus intercalatus becomes more complex in appearance. The adult SP pattern is formed by P60 when the dorsal commissural nucleus dense core becomes the last autonomic region to be SP innervated. In addition, a transient population of immunohistochemically demonstrable cervical-thoracic laminae VII and X SP cell bodies are observed from P2 to P15.

Neuropeptide Y immunoreactivity is preferentially located in rat lumbar sexually dimorphic nuclei

The distribution of neuropeptide Y-like immunoreactivity (NPY-LI) was examined in the ventral gray lumbar spinal cord of male and female rats. Fibers containing NPY-LI were distributed in a sexually dimorphic manner in three motor nuclei: the male cremaster nucleus (CN), spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus, pars medialis (mDLN) receive a greater number of fibers with NPY-LI than females. Fibers with NPY-LI had the following ratios: males, mDLN greater than or equal to SNB greater than CN greater than dorsolateral nucleus, pars lateralis (1DLN) greater than remaining lumbar ventral gray horn motoneurons (VGH); females, mDLN greater than or equal to SNB greater than or equal to CN greater than VGH greater than or equal to 1DLN. In addition, a previously undescribed small column of motoneurons, located between mDLN and SNB, is outlined by fibers which contain NPY-LI in both sexes. The role of NPY in lumbar sexually dimorphic nuclei is presently unknown.

Neuropeptides and neuropathology in the amygdala in Alzheimer's disease: relationship between somatostatin, neuropeptide Y and subregional distribution of neuritic plaques

This study examined the amygdaloid complex in Alzheimer's disease (AD). We compared the distribution and morphology of somatostatin (SOM-) and neuropeptide Y-immunoreactive (NPY-IR) neurons in the amygdala with the distribution of neuritic plaques (NP) and acetylcholinesterase (AChE) staining patterns in various subnuclei. We found that in AD, there was an increase in the number of small, atrophic neurons for both SOM and NPY, and subregional analysis revealed similar size reductions in all subnuclei. In contrast, the highest density of NP was found in the corticomedial nuclei and densest staining for AChE in the basal nucleus. Although NPY- and SOM-IR fibers were occasionally associated with NP, a dense, morphologically preserved peptidergic fiber-network was found in all areas including subnuclei with high numbers of NP. Our study indicates that atrophic SOM- and NPY-IR neurons are not correlated with the subregional distribution of NP or cholinesterase staining pattern of the amygdala, and suggests that alterations in SOM and NPY neurons are not characteristics of the primary pathogenic process that underlie the formation of NP or cholinergic cell loss in AD.

Free and total catecholamines in critical illness

The magnitude of circulating free and total (free plus conjugated) catecholamine responses to a strong and sustained stimulus was investigated in four groups of patients: traumatic brain injury (n = 24), vascular brain injury (n = 10), polysystem trauma (n = 7) and medical/surgical patients in an intensive care unit (n = 29). Despite significant three- to sevenfold elevations in both free and total norepinephrine (NE) and epinephrine (E), the ratio of free to total NE and E remained constant over a very broad range of values. The proportion of free E was twice normal (30.1-33.5 vs. 16.2%) in all but patients with polytrauma, whereas the percentage of free NE was unchanged in all patients (43.0%). All dopamine (DA) parameters remained generally normal. In the patients with traumatic or vascular brain injury, significant inverse correlations were present between the degree of neurological dysfunction, as indicated by the concomitant Glasgow coma score, and free NE, E, and DA and total NE and DA levels. Thus, during conditions of intense and prolonged catecholamine release, the proportion of free catecholamine remains constant and the total as well as free catecholamine concentration is proportional to the Glasgow coma score.

The morphology and distribution of rat serotoninergic intraspinal neurons: an immunohistochemical study

An immunohistochemically derived morphological description of a diverse population of rat lamina VII and X intraspinal 5HT neurons is provided. These bipolar or multipolar neurons occur most frequently in lamina X, dorsal or dorsolateral to the central canal, in thoracolumbar, sacral, and coccygeal spinal segments. These 5HT intraspinal neurons are found in normal rat spinal cords as well as in spinal cords that have been hemisected or transected 60 days prior to serotonin immunostaining. Therefore, 5HT intraspinal neurons are the probable source of the biochemically detectable 5HT that remains in the spinal cord distal to a spinal transection. In the rat, serotonin intraspinal neurons are most often associated with spinal autonomic nuclei but it is unknown if they are preganglionic in nature.

Thyroid test abnormalities in traumatic brain injury: correlation with neurologic impairment and sympathetic nervous system activation

Acute illness is well known to affect thyroid function, but there are few studies correlating the severity of the underlying medical problem with indexes of thyroid function and little is known about its cause. Traumatically brain-injured patients were selected because they were a relatively homogeneous, previously healthy group with a condition whose severity was readily quantifiable. In 66 such patients, the relationships between changes in thyroid function tests (thyroxine, free thyroxine, triiodothyronine, reverse triiodothyronine, and thyrotropin levels), catecholamine and cortisol concentrations measured on admission and again four days after the accident, and neurologic function assessed by the Glasgow Coma Score (GCS) were studied. Triiodothyronine and thyroxine levels fell significantly within 24 hours of injury. Four days after the accident, patients with the greatest neurologic dysfunction had the lowest triiodothyronine and thyroxine levels; significant correlations were present between the Day 4 GCS and concomitant thyroxine (r = 0.47, p less than 0.0001), free thyroxine (r = 0.32, p less than 0.02), and triiodothyronine (r = 0.50, p less than 0.0001) levels. Reverse triiodothyronine values remained unchanged throughout the study even in the most severely affected patients; the rise in thyrotropin levels was not significant (1.2 +/- 0.2 to 1.7 +/- 0.3 microU/ml, p = NS). Patients who died or remained vegetative had thyroxine and triiodothyronine levels 30 percent to 50 percent lower than those who had a good recovery (p less than 0.05). Highly significant correlations were present between Day 4 thyroxine and triiodothyronine levels and admission and Day 4 norepinephrine and epinephrine concentrations. There was no association between admission or concomitant cortisol levels and thyroid function on Day 4; treatment with high-dose dexamethasone did not influence these indexes. Thus, patients with traumatic brain injury exhibit a gradient of thyroid dysfunction that occurs promptly, is dependent upon the degree of neurologic impairment, and reflects ultimate outcome. The significant association with catecholamine levels suggests a role for sympathetic nervous system activation in its causation, independent of a generalized stress response, since there is no correlation of thyroid test abnormality with the degree of adrenocortical secretion.

Biochemical and morphological effects of castration on the postorganizational development of the hypogastric ganglion

The biochemical and morphological development of the sympathetic hypogastric ganglion (HG) was examined subsequent to postnatal castration at 10-11 days of age. Previous studies suggested that tyrosine hydroxylase (T-OH) activity, an index of noradrenergic maturation, and choline acetyltransferase (ChAT) activity, a marker for preganglionic terminal formation, were dependent on gonadal hormones during normal ontogeny. In the present studies, morphometric analyses of the HG revealed that the cross-sectional area of the cell soma and nucleus were significantly reduced following postnatal castration at day 10. Conversely, castration produced no change in the number of HG neurons. In addition, postnatal castration prevents the development of postsynaptic T-OH activity to a greater extent than ganglionic protein resulting in a significant loss of T-OH specific activity. In contrast, presynaptic ChAT activity was reduced in parallel with ganglionic protein, thus ChAT specific activity was unchanged. Testosterone replacement therapy, even in groups where treatment was delayed for up to 2 weeks after castration, completely reversed deficits in both T-OH and ChAT activities. These studies suggest that altered development of ganglion protein subsequent to postnatal castration is related to decreases in the size of neurons and not to the loss of neurons. The lack of cell loss also suggest that decreased levels of postsynaptic T-OH activity results from a loss of enzyme activity per cell and the decreased levels of ChAT activity probably represent fewer presynaptic terminals per neuron. In addition, delayed testosterone replacement subsequent to castration was effective in restoring enzyme activities suggesting an 'activational' not 'organizational' role for testosterone after postnatal day 10.

Enkephalin fibers in autonomic nuclear regions: intraspinal vs. supraspinal origin

The present studies in the rat employ spinal transections and hemisections, dorsal and/or ventral rhizotomies to determine whether enkephalin fibers in spinal sympathetic and parasympathetic nuclei are of supraspinal, intraspinal, or peripheral origin. Our results suggest enkephalin fibers in thoracolumbar sympathetic nuclei are of both supraspinal and intraspinal origin, whereas the enkephalin innervation of the sacral parasympathetic nucleus is primarily intraspinal in origin. Furthermore, the majority of descending enkephalin systems selectivity project to the intermediolateralis, pars principalis and pars funicularis, and the dorsal commissural sympathetic nuclei, whereas intraspinal enkephalin pathways appear to exist primarily in the intercalatus spinalis and intercalatus spinalis, pars paraependymalis sympathetic nuclei. These new observations suggest that specific patterns exist for supraspinal and intraspinal enkephalin pathways.

The major pelvic ganglion: androgen control of postnatal development

Previously we reported the effects of postnatal castration on the postorganizational development of the sympathetic hypogastric ganglion (Hamill and Guernsey, 1983; Melvin and Hamill, 1986). "Postorganization" implies an activational role for gonadal hormones, in contrast to the permanent organizing effects that occur perinatally. We now report results that suggest that the major pelvic ganglion (PG), a mixed parasympathetic and sympathetic ganglion, is similarly regulated by testosterone during development. Choline acetyltransferase (CAT) and tyrosine hydroxylase (T-OH) activities were used to examine normal PG ontogeny. The normal development of these biochemical indices occurs primarily after day 10. Postnatal castration at 10-11 d of age completely prevented the postorganizational developmental increase of T-OH activity. At 12 postoperative weeks T-OH activity in castrates was approximately 6% that of the control animals (control, 2880 +/- 127 pmol/ganglion X hr; castrated, 161 +/- 16 pmol/ganglion X hr; p less than 0.001). In fact, by only 1 postoperative week, T-OH activity was already significantly reduced in castrated animals (control, 480 +/- 69 pmol/ganglion X hr; castrated, 179 +/- 6 pmol/ganglion X hr; p less than 0.001). CAT activity and total ganglion protein were also significantly reduced by 1 postoperative week. In contrast to T-OH activity, however, these indices continued to develop at diminished rates. By 12 postoperative weeks CAT activity and total ganglion protein in castrates were 30 and 50% of control values, respectively, resulting in a significant developmental abnormality in CAT-specific activity. Testosterone replacement reversed the castration-induced developmental deficits of T-OH and CAT activities.(ABSTRACT TRUNCATED AT 250 WORDS)

The predictive value of catecholamines in assessing outcome in traumatic brain injury

Because of the central role of the sympathetic nervous system in mediating the stress response, plasma norepinephrine (NE), epinephrine (E), and dopamine (DA) levels were measured in 61 traumatically brain-injured patients to determine whether catecholamine (CA) levels obtained within 48 hours after injury provide reliable prognostic markers of outcome. Patient outcome was determined at 1 week using the Glasgow Coma Scale (GCS) and at the time of discharge using the Glasgow Outcome Scale (GOS). Levels of NE, E, and DA correlated highly with the admission GCS score (NE: r = 0.58, p less than 0.0001; E: r = 0.46, p less than 0.0025; DA: r = 0.27, p less than 0.04). Moreover, in the 21 patients with GCS scores of 3 or 4 on admission, NE levels predicted outcome at 1 week. All six patients with NE levels less than 900 pg/ml (normal level less than 447 pg/ml) improved to GCS scores of greater than 11, while 12 of 15 with NE values greater than 900 pg/ml remained with GCS scores of 3 to 6 or died. Levels of E and DA were not as useful. Catecholamine levels also increased significantly as the GOS score worsened. Levels of NE and E were significantly higher in patients who died or remained persistently vegetative than in those with better outcomes. In the 54 patients who survived beyond 1 week, significant correlations were present between the length of hospitalization and NE (r = 0.71, p less than 0.0001) and E (r = 0.61, p less than 0.0001) levels. Concentrations of NE (r = 0.61, p less than 0.0004) and E (r = 0.48, p less than 0.01) were also highly correlated with the duration of ventilatory assistance. Analysis of the interactions of CA levels and GCS scores, duration of ventilatory assistance, and length of hospitalization revealed that the CA's either enhanced the reliability of the GCS score or were independent predictors of outcome. Thus, these findings indicate that alterations in circulating CA levels reflect the severity of the neurological insult and provide support for the use of CA measurements as a physiological marker of patient outcome in both the acute and chronic phases of traumatic brain injury.

Catecholamines predict outcome in traumatic brain injury

Activation of the sympathetic nervous system attends traumatic brain injury, but the association of the severity of neurological impairment and recovery with the extent of sympathetic nervous system stimulation is poorly defined. In this study, plasma norepinephrine (NE), epinephrine (E), and dopamine (DA) levels were measured serially in 33 patients with traumatic brain injury and compared with the Glasgow Coma Score (GCS), which was obtained concurrently. A catecholamine gradient that reflected the extent of brain injury was demonstrated within 48 hours of the injury. In patients with a GCS of 3 to 4, NE and E levels increased four- to fivefold and the DA level increased threefold above normal (NE, 1686 +/- 416 pg/ml; E, 430 +/- 172 pg/ml; DA, 236 +/- 110 pg/ml), while patients with mild brain injury (GCS, greater than 11) had slightly elevated or normal levels. Patients with marked (GCS, 5 to 7) and moderate (GCS, 8 to 10) traumatic brain injuries had intermediate levels. The prognostic value of determining admission levels of NE was shown in patients with an admission GCS of 3 to 4 1 week after injury. Patients with severe and unchanging neurological impairment 1 week after injury had markedly elevated initial NE levels (2,176 +/- 531 pg/ml), whereas initial NE levels (544 +/- 89 pg/ml) were only mildly elevated in patients who improved to a GCS of greater than 11. These data indicate that markedly elevated NE levels predict outcome in patients with comparable neurological deficits. Thus levels of circulating catecholamines are excellent endogenous and readily quantifiable markers that appear to reflect the extent of brain injury and that may predict the likelihood of recovery.

Altered sympathetic-salivary gland development: delayed response to postnatal castration

These studies defined the normal and hormonally altered development of activity for tyrosine hydroxylase (T-OH), the rate-limiting enzyme in catecholamine biosynthesis (Levitt et al., 1965), and choline acetyltransferase activity (CAT) in the male rat superior cervical ganglion (SCG). Additionally, salivary gland weight was monitored. Two distinct developmental plateaus for postsynaptic T-OH activity exist. The first plateau represents the prepubertal level, which is significantly lower than the second postpubertal plateau. In contrast, presynaptic CAT activity displayed only a single plateau, commencing at approximately 45 days of age. The effects of postnatal castration (at 10 or 11 days of age) on the submandibular gland and T-OH activity were delayed until after puberty. No change in T-OH activity was seen at two and four post-operative weeks between control and castrated animals; however, T-OH activity was significantly less in castrated animals at 12 and 16 post-operative weeks. Testosterone replacement reversed the effect of castration on T-OH activity. Conversely, CAT activity in the SCG was unchanged by postnatal castration for at least 16 post-operative weeks, the longest time point studied. The failure of castrated animals to display the normal developmental increase in T-OH activity following puberty was comparable with the effect of castration on the development of submandibular salivary gland weight. These results suggest that in postpubertal male rats, development of T-OH activity in the superior cervical ganglion is influenced by testosterone. The parallel effects of castration on submandibular gland weight imply that testosterone regulates T-OH activity via an indirect mechanism. In contrast to noradrenergic enzyme activity and target tissue size, the ontogeny of presynaptic CAT activity appears to be insensitive to testosterone levels.

Central neurotoxic effects of guanethidine: altered serotonin and enkephalin neurons within the area postrema

This study reveals that the 5-HT and enkephalin cell body population of the area postrema (AP) is dramatically reduced via exposure to the peripherally circulating neurotoxin guanethidine. Efforts to restore cell body numbers to control levels, with colchicine and monoamine oxidase inhibitors, subsequent to guanethidine treatment are ineffective. However, 5-HT and enkephalin immunostaining of surrounding bulbar nuclei appears normal, implying that the neurotoxic effect of guanethidine is restricted to the AP. In addition, gamma-aminobutyric acid and neurotensin immunostaining within the AP appears normal, subsequent to guanethidine treatment, suggesting that the neurotoxic effect is restricted to specific AP cell populations.

Gonadal hormone regulation of neurotransmitter synthesizing enzymes in the developing hypogastric ganglion

The effects of postnatal castration at 10-11 days of age were examined in the sympathetic hypogastric ganglion (HG). Assays for choline acetyltransferase (ChAT) activity, a biochemical marker for presynaptic cholinergic maturation, and the activity of tyrosine hydroxylase (T-OH), the rate limiting enzyme in postsynaptic catecholamine biosynthesis and an index of noradrenergic development, were employed to monitor HG ontogeny. After 1 postoperative week ChAT activity and T-OH activity were significantly reduced in castrated animals as compared to sham operated controls. Over the 12 week postoperative observation period T-OH activity never varied significantly from the day 10 precastration value; thus, by 12 postoperative weeks T-OH activity in the castrated animals was 3% of the control value. In contrast, ChAT activity and total ganglion protein continued to mature in the castrated animals, but at diminished rates, so that by 12 postoperative weeks both indices were approximately 40% of the control values. Testosterone replacement therapy restored both ChAT and T-OH activities to control levels. Additionally, testosterone replacement restored the control level of activity for DOPA decarboxylase, a catecholamine synthetic enzyme which is differentially regulated from T-OH. The failure of enzyme activities to develop normally subsequent to castration on postnatal day 10 suggests that testosterone regulates the postorganizational maturation of postsynaptic noradrenergic enzyme activities and presynaptic ChAT activity.

Transient hypogonadotrophic hypogonadism after head trauma: effects on steroid precursors and correlation with sympathetic nervous system activity

Transient hypogonadotrophic hypogonadism commonly occurs after major medical insults. Because data on testosterone precursors are sparse and because little is known about the aetiology of these changes, we studied the interactions of traumatic brain injury with gonadal steroidogenesis and with sympathetic nervous system activation. Patients were divided into two groups based upon the severity of neurological dysfunction using the Glasgow Coma Score (GCS); Group 1 less than 8, Group 2 greater than or equal to 8. Group 1 was further divided into those patients treated (Group 1b) and those not treated with dexamethasone (Group 1a). Plasma levels of testosterone, androstenedione, 17-hydroxyprogesterone, DHEA sulphate, cortisol, LH, FSH, and the catecholamines noradrenaline (NE), adrenaline (EPI) and dopamine were measured in 31 acutely brain injured men, aged 18-95, shortly after their accident and 4 days later. In all patients, NE and EPI were elevated on admission (NE: 841 +/- 105 (SEM) pg/ml; EPI: 191 +/- 32 pg/ml and there were highly significant inverse correlations between admission NE (r = -0.52, P less than 0.003) and EPI (r = 0.44, P less than 0.02) levels and day 4 testosterone concentrations. Testosterone fell 53% (P less than 0.001) in 13 Group 1a men, but only 25% (P = NS) in the less severely injured. Similar reductions occurred in cortisol and the steroid precursors. However, only testosterone, 17-hydroxyprogesterone, and DHEA sulphate levels were significantly lower than normal on day 4. LH and FSH levels were also significantly reduced from elevated admission levels. In the eight men treated with dexamethasone (8-40 mg/ml) (Group 1b), the decrease in testosterone, LH and FSH concentrations were similar to those present in Group 1a. Thus, severe traumatic brain injury leads to hypogonadotrophic hypogonadism which affects testosterone and its precursors. The magnitude of the hormonal dysfunction is dependent upon the severity of the neurological insult. Finally, the decrease in testosterone is significantly correlated with admission catecholamine levels, which may suggest a role for the sympathetic nervous system (SNS) in mediating this response in men.