Comparison of Growth Curve Estimates of Infants in São Tomé Island, Africa, with the WHO Growth Standards: A Birth Cohort Study

This birth cohort study compared the infant growth curve estimates in São Tomé Island to the WHO growth standards. Despite this island belonging to a lower-middle-income country, there were several factors favorable for growth that were present. Four-hundred and seventy-five full-term singleton appropriate for-gestational-age infants were enrolled and followed-up to 24 months of age. Weight-for-age, length-for-age, weight-for-length, body mass index-for-age, head circumference-for-age, weight velocity, and length velocity curves were estimated and compared to the WHO standards. In the first 6 months of age, the weight gain was adequate in the presence of a high prevalence of exclusive breastfeeding. Thereafter, weight trajectories tracked close to the WHO standards, except for a progressive decline in the infants growing in higher percentiles, especially in girls. Median length at birth was below the median WHO standards, followed by an early postnatal velocity spurt, which probably reflected the transition from an unfavorable to a more favorable postnatal environment. Thereafter, linear growth faltering was observed without relevant deterioration up to 24 months of age, which was probably due to the presence of protective factors. These results may be useful to implement strategies to further approximate infant growth in São Tomé Island to the WHO standards.

Subclinical Enteric Parasitic Infections and Growth Faltering in Infants in São Tomé, Africa: A Birth Cohort Study

The associations between enteric pathogenic parasites and growth in infants in São Tomé were explored using a refined anthropometric approach to recognize early growth faltering. A birth cohort study was conducted with follow-up to 24 months of age. Microscopic examination for protozoa and soil-transmitted helminths was performed. Anthropometric assessments included: z-scores for weight-for-length (WLZ), length-for-age (LAZ), weight (WAVZ) and length velocities (LAVZ), length-for-age difference (LAD), and wasting and stunting risk (≤-1 SD). Generalized additive mixed effects regression models were used to explore the associations between anthropometric parameters and enteric parasitic infections and cofactors. A total of 475 infants were enrolled, and 282 completed the study. The great majority of infants were asymptomatic. Giardia lamblia was detected in 35.1% of infants in at least one stool sample, helminths in 30.4%, and Cryptosporidium spp. in 14.7%. Giardia lamblia and helminth infections were significantly associated with mean decreases of 0.10 in LAZ and 0.32 in LAD, and of 0.16 in LAZ and 0.48 in LAD, respectively. Cryptosporidium spp. infection was significantly associated with a mean decrease of 0.43 in WAVZ and 0.55 in LAVZ. The underestimated association between subclinical parasitic enteric infections and mild growth faltering in infants should be addressed in public health policies.

Valores normativos de la fuerza de puño en la población española en edad laboral. Influencia de las variables antropométricas de la mano y el antebrazo

Objetivos: Determinar si en los individuos adultos sanos existe una apertura óptima del dinamómetro para conseguir la máxima fuerza de puño y si esta se relaciona con los valores de los parámetros antropométricos del antebrazo y la mano. Saber si a través de las medidas antropométricas del antebrazo y la mano es posible predecir la fuerza de puño que puede desarrollar un persona.

Métodos: 99 hombres y 103 mujeres (20-60 años). Cada mano se testó 10 veces, utilizando 5 aperturas del dinamómetro TKK. Las medidas antropométricas tomadas fueron ancho de la mano abierta, longitud del segundo, el tercer y el cuarto dedos, anchura de la palma, longitud de la palma, longitud de la mano, longitud del antebrazo, perímetro del antebrazo y grosor de la eminencia tenar.

Resultados: Con solo 2 aperturas (5,5-6 cm en varones, 5-5,5 cm en mujeres) se consiguió la máxima fuerza de puño en más del 60% de los individuos. El tamaño de la mano y el antebrazo influyó en la posición de apertura óptima en las mujeres, no en los varones. Los parámetros antropométricos que mejor definieron la fuerza fueron diferentes según el sexo y el lado, pero en ningún caso se logró que el valor de R2 superase el 0,50.

Conclusiones: La máxima fuerza de puño se consigue utilizando las posiciones medias del dinamómetro, siendo en mujeres la apertura menor que en varones. Empleando exclusivamente los parámetros antropométricos de la mano y el antebrazo no se consigue un valor predictivo útil, como el obtenido por otros autores con otras medidas antropométricas.

Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The objective of this review is to assess the visual effects of implantation of trifocal intraocular lenses compared with bifocal intraocular lenses during cataract surgery among presbyopic patients.

Association of enteric parasitic infections with intestinal inflammation and permeability in asymptomatic infants of São Tomé Island

The cumulative effect of repeated asymptomatic enteric infections on intestinal barrier is not fully understood in infants. We aimed to evaluate the association between previous enteric parasitic infections and intestinal inflammation and permeability at 24-months of age, in asymptomatic infants of São Tomé Island. A subset of infants from a birth cohort, with intestinal parasite evaluations in at least four points of assessment, was eligible. Intestinal inflammatory response and permeability were assessed using fecal S100A12 and alpha-1-antitrypsin (A1AT), respectively. The cutoff <-1SD for weight-for-length and length-for-age was used to define wasting and stunting. Multivariable linear regression analysis explored if cumulative enteric parasitic infections explained variability of fecal biomarkers, after adjusting for potential confounders. Eighty infants were included. Giardia duodenalis and soil-transmitted helminths (STH) were the most frequent parasites. The median (interquartile range) levels were 2.87 μg/g (2.41-3.92) for S100A12 and 165.1 μg/g (66.0-275.6) for A1AT. Weak evidence of association was found between S100A12 levels and G. duodenalis (p = 0.080) and STH infections (p = 0.089), and between A1AT levels and parasitic infection of any etiology (p = 0.089), at 24-months of age. Significant associations between A1AT levels and wasting (p = 0.006) and stunting (p = 0.044) were found. Previous parasitic infections were not associated with fecal biomarkers at 24 months of age. To summarize, previous asymptomatic parasitic infections showed no association with intestinal barrier dysfunction. Notwithstanding, a tendency toward increased levels of the inflammatory biomarker was observed for current G. duodenalis and STH infections, and increased levels of the permeability biomarker were significantly associated with stunting and wasting.

Dopamine D₂ and acetylcholine α7 nicotinic receptors have subcellular distributions favoring mediation of convergent signaling in the mouse ventral tegmental area

Alpha7 nicotinic acetylcholine receptors (α7nAChRs) mediate nicotine-induced burst-firing of dopamine neurons in the ventral tegmental area (VTA), a limbic brain region critically involved in reward and in dopamine D2 receptor (D2R)-related cortical dysfunctions associated with psychosis. The known presence of α7nAChRs and Gi-coupled D2Rs in dopamine neurons of the VTA suggests that these receptors are targeted to at least some of the same neurons in this brain region. To test this hypothesis, we used electron microscopic immunolabeling of antisera against peptide sequences of α7nACh and D2 receptors in the mouse VTA. Dual D2R and α7nAChR labeling was seen in many of the same somata (co-localization over 97%) and dendrites (co-localization over 49%), where immunoreactivity for each of the receptors was localized to endomembranes as well as to non-synaptic or synaptic plasma membranes often near excitatory-type synapses. In comparison with somata and dendrites, many more small axons and axon terminals were separately labeled for each of the receptors. Thus, single-labeled axon terminals were predominant for both α7nAChR (57.9%) and D2R (89.0%). The majority of the immunolabeled axonal profiles contained D2R-immunoreactivity (81.6%) and formed either symmetric or asymmetric synapses consistent with involvement in the release of both inhibitory and excitatory transmitters. Of 160 D2R-labeled terminals, 81.2% were presynaptic to dendrites that expressed α7nAChR alone or together with the D2R. Numerous glial processes inclusive of those enveloping either excitatory- or inhibitory-type synapses also contained single labeling for D2R (n=152) and α7nAChR (n=561). These results suggest that classic antipsychotic drugs, all of which block the D2R, may facilitate α7nAChR-mediated burst-firing by elimination of D2R-dependent inhibition in neurons expressing both receptors as well as by indirect pre-synaptic and glial mechanisms.

Medial prefrontal cortex receives input from dorsal raphe nucleus neurons targeted by hypocretin1/orexinA-containing axons

The medial prefrontal cortex (mPFC) is strongly involved in cognition and behavior. It receives input from brainstem nuclei implicated in behavioral wakefulness and electrographic cortical activation, such as the dorsal raphe nucleus (DRN). Moreover, the hypocretinergic/orexinergic (Hcrt/Ox) hypothalamic neurons innervate DRN, thus modulating its activity and presumably allowing transitions between sleep-wakefulness cycle states. Dysfunction in this system is associated with narcolepsy. In this study we aimed to determine the precise location of DRN neurons projecting to mPFC and the extent to which they contain serotonin (5-hydroxytryptamine); we have also assessed whether Hcrt1/OxA neurons innervate DRN neurons that could sustain behavioral wakefulness through their projections to mPFC. The retrograde tracer Fluorogold was injected into mPFC and DRN sections were processed for double immunolabeling of anti-Fluorogold and either anti-5-hydroxytryptamine or anti-Hcrt1/OxA antisera. Most DRN neurons projecting to mPFC were located in the ventral sector of the rostral and intermediate DRN, and around half of them were serotonergic. Hcrt1/OxA-immunoreactivity in DRN was observed in unmyelinated axons and axon boutons (varicosities or axon terminals). Hcrt1/OxA immunoreactivity was observed within the cytoplasm and in dense-cored vesicles of these axons. Hcrt1/OxA-labeled boutons established both asymmetric synapses (n=30) and appositional contacts (n=102) with Fluorogold-labeled dendrites belonging to DRN neurons projecting to mPFC. Our results show that Hcrt1/OxA neurons may exert a direct synaptic influence on DRN neurons that could facilitate wakefulness, although other non-synaptic actions through volume transmission are also suggested.

Hypocretin/Orexin neuropeptides: participation in the control of sleep-wakefulness cycle and energy homeostasis

Hypocretins or orexins (Hcrt/Orx) are hypothalamic neuropeptides that are synthesized by neurons located mainly in the perifornical area of the posterolateral hypothalamus. These hypothalamic neurons are the origin of an extensive and divergent projection system innervating numerous structures of the central nervous system. In recent years it has become clear that these neuropeptides are involved in the regulation of many organic functions, such as feeding, thermoregulation and neuroendocrine and cardiovascular control, as well as in the control of the sleep-wakefulness cycle. In this respect, Hcrt/Orx activate two subtypes of G protein-coupled receptors (Hcrt/Orx1R and Hcrt/Orx2R) that show a partly segregated and prominent distribution in neural structures involved in sleep-wakefulness regulation. Wakefulness-enhancing and/or sleep-suppressing actions of Hcrt/Orx have been reported in specific areas of the brainstem. Moreover, presently there are animal models of human narcolepsy consisting in modifications of Hcrt/Orx receptors or absence of these peptides. This strongly suggests that narcolepsy is the direct consequence of a hypofunction of the Hcrt/Orx system, which is most likely due to Hcrt/Orx neurons degeneration.

The main focus of this review is to update and illustrate the available data on the actions of Hcrt/Orx neuropeptides with special interest in their participation in the control of the sleep-wakefulness cycle and the regulation of energy homeostasis. Current pharmacological treatment of narcolepsy is also discussed.

[Clinical and epidemiological characterisation of dengue haemorrhagic fever in Neiva, Colombia, 2004]

OBJECTIVE

Neiva (a southern Colombia city) is endemic for dengue fever and dengue haemorrhagic fever. Neiva has suffered outbreaks of dengue, that in 2004 being the latest one. This study was designed to characterise epidemiological and clinical data from that outbreak of dengue.

MATERIAL AND METHODS

This was a descriptive, retrospective study of children aged less than 13 years who were admitted to the University Hospital and fulfilled the WHO's clinical and laboratory criteria for dengue or dengue haemorrhagic fever. Demographic, clinical and paraclinical data were recorded and analysed using Chi square (chi(2)) bivariate tabular test.

RESULTS

105 children were diagnosed as suffering from either dengue haemorrhagic fever (87.6%) or dengue fever (12.4%); 67% of them were aged less than 5 years. Girls were more frequently affected by severe clinical manifestations. 83% of the children were admitted during the first six days of the disease; dengue shock syndrome was diagnosed in 20% and 76% presented clinical complications (chi(2) 29.53, gl 6, p=0.0000). Aminotransferases were 3 to 5 times above normal levels. There was a statistical correlation between low platelet count (less than 20 000 per mm(3)) and shock during admission (chi(2) 20.65, gl 4, p=0.0004). Complications arose during clinical evolution in 32% of the cases (13% myocarditis, 19% hepatitis or encephalitis and 2% sepsis).

CONCLUSION

The clinical and epidemiological characteristics observed in this cohort evidenced differences in age, gender and organs affected compared to data described in the literature; there was a high incidence of myocarditis.

[Modulation by the hypocretinergic/orexinergic neurotransmission system in sleep-wakefulness cycle states]

INTRODUCTION

The hypocretins/orexins are neuropeptides synthesized by a small neuronal cell group located in the posterior and lateral hypothalamus. These peptides have been considered modulators of the sleep-wakefulness cycle since their discovery in 1998; the hypocretinergic/orexinergic system is very active during wakefulness. In addition, the absence of either these peptides or their receptors is associated to narcolepsy-cataplexy, a disease in which the sleep-wakefulness cycle is completely disorganized.

DEVELOPMENT

Hypocretinergic/orexinergic neurons directly activate the cerebral cortex and neuronal cell groups of the reticular activating system containing noradrenaline, serotonin, dopamine, acetylcholine and histamine, through which they may also indirectly activate the cerebral cortex and enhance wakefulness; as well, these neurons inhibit REM sleep generation in the ventral pontine tegmentum. The decrease in the activity of hypocretinergic/orexinergic neurons during sleep inhibits the aminergic and cholinergic neurons of the reticular activating core, decreasing cortical activation and renewing REM sleep generation in the ventral pontine tegmentum.

CONCLUSIONS

Hypocretins/orexins modulate wakefulness and EEG activation in part through their actions on reticular core neurons projecting to the cortex and suppress REM sleep generation through inhibition of ventral pontine tegmentum neurons within the ventral oral pontine tegmentum. The hypoactivity of this system supports the sleep cycle fragmentation and general disorganization appearing in narcolepsy, as well as momentary interruption of wakefulness by REM sleep episodes.

Relationship between the perifornical hypothalamic area and oral pontine reticular nucleus in the rat. Possible implication of the hypocretinergic projection in the control of rapid eye movement sleep

The perifornical (PeF) area in the posterior lateral hypothalamus has been implicated in several physiological functions including the regulation of sleep-wakefulness. Some PeF neurons, which contain hypocretin, have been suggested to play an important role in sleep-wake regulation. The aim of the present study was to examine the effect of the PeF area and hypocretin on the electrophysiological activity of neurons of the oral pontine reticular nucleus (PnO), which is an important structure in the generation and maintenance of rapid eye movement sleep. PnO neurons were recorded in urethane-anesthetized rats. Extracellular recordings were performed by means of tungsten microelectrodes or barrel micropipettes. Electrical stimulation of the ipsilateral PeF area elicited orthodromic responses in both type I (49%) and type II (58%) electrophysiologically characterized PnO neurons, with a mean latency of 13.0 +/- 2 and 8.3 +/- 5 ms, respectively. In six cases, antidromic spikes were evoked in type I PnO neurons with a mean latency of 3.2 +/- 0.4 ms, indicating the existence of PnO neurons that projected to the PeF area. Anatomical studies showed retrogradely labeled neurons in the PeF area from the PnO. Some of these neurons projecting to the PnO contained hypocretin (17.8%). Iontophoretic application of hypocretin-1 through a barrel micropipette in the PnO induced an inhibition, which was blocked by a previous iontophoretic application of bicuculline, indicating that the inhibitory action of hypocretin-1 may be due to activation of GABA(A) receptors. These data suggest that the PeF area may control the generation of rapid eye movement sleep through a hypocretinergic projection by inhibiting the activity of PnO neurons.

Clinical and ethical implications of genetic counselling in familial adenomatous polyposis

The association of specific genetic disturbances with the development of hereditary cancer helps us to understand the risk of suffering from it, the possibility of an earlier diagnosis, and the treatment and prevention of this disease. Familial adenomatous polyposis (FAP) is a pre-neoplastic syndrome characterized by the presence of hundreds of adenomatous polyps in the colon, which develop into a carcinoma. FAP can be diagnosed using sequencing techniques to detect mutations in the germinal line of the APC (adenomatous polyposis coli) gene. The genetic diagnostic approach in families with FAP, previously followed up in the Gastrointestinal Clinic, has both advantages and disadvantages, and places us nearer the disease and patient. Disclosing the results of this genetic test entails relevant problems in clinical practice, which affect the health field and raise legal and ethical issues, along with the familial, occupational, and social implications that knowing the genetic status can have on the patient. Genetic analysis is rare in normal clinical practice, which involves errors in the interpretation of the results obtained, and during the process of genetic counselling. Specialized multidisciplinary units are necessary for the management of patients with FAP undergoing analysis and appropriate genetic counselling, thus providing an individualized service. The creation of FAP registers and protocols for this healthcare process should optimize the management of these patients and their families.

Ultrastructural localization of enkephalin and mu-opioid receptors in the rat ventral tegmental area

Enkephalins are endogenous ligands for opioid receptors whose activation potently modulates the output of mesocorticolimbic dopaminergic neurons within the ventral tegmental area. Many of the reinforcing effects of enkephalins in the mesocorticolimbic system are mediated by mu-opioid receptors. To determine the sites for Leu(5)-enkephalin activation of mu-opioid receptors in the ventral tegmental area, we examined the dual electron microscopic immunocytochemical localization of their respective antigens in this region of rat brain. Enkephalin immunoperoxidase reaction product and mu-opioid receptor immunogold-silver labeling showed similar cellular and subcellular distribution in both the paranigral and parabrachial subdivisions of the ventral tegmental area. Enkephalin immunoreactivity was mainly localized in small unmyelinated axons (50.4%) and in axon terminals (40.4%). The majority of these terminals formed symmetric, inhibitory-type synapses, many of which were on dendrites expressing plasmalemmal mu-opioid receptors. Appositional contacts were also often seen between axons or terminals that were differentially labeled for the two antigens. In addition, some of the enkephalin-labeled terminals and a few somatodendritic profiles showed a plasmalemmal or vesicular localization of mu-opioid receptors. Our results indicate that dendritic targets of inhibitory terminals, as well as nearby axon terminals, are potential sites for enkephalin activation of mu-opioid receptors throughout the ventral tegmental area. Moreover, co-localization of enkephalin and mu-opioid receptors in selective neuronal profiles may indicate an autoregulatory role for these receptors or their internalization along with the bound ligand in this brain region.

Plasmalemmal mu-opioid receptor distribution mainly in nondopaminergic neurons in the rat ventral tegmental area

Opiate-evoked reward and motivated behaviors reflect, in part, the enhanced release of dopamine produced by activation of the mu-opioid receptor (muOR) in the ventral tegmental area (VTA). We examined the functional sites for muOR activation and potential interactions with dopaminergic neurons within the rat VTA by using electron microscopy for the immunocytochemical localization of antipeptide antisera raised against muOR and tyrosine hydroxylase (TH), the synthesizing enzyme for catecholamines. The cellular and subcellular distribution of muOR was remarkably similar in the two major VTA subdivisions, the paranigral (VTApn) and parabrachial (VTApb) nuclei. In each region, somatodendritic profiles comprised over 50% of the labeled structures. MuOR immunolabeling was often seen at extrasynaptic/perisynaptic sites on dendritic plasma membranes, and 10% of these dendrites contained TH. MuOR-immunoreactivity was also localized to plasma membranes of axon terminals and small unmyelinated axons, none of which contained TH. The muOR-immunoreactive axon terminals formed either symmetric or asymmetric synapses that are typically associated with inhibitory and excitatory amino acid transmitters. Their targets included unlabeled (30%), muOR-labeled (25%), and TH-labeled (45%) dendrites. Our results suggest that muOR agonists in the VTA affect dopaminergic transmission mainly indirectly through changes in the postsynaptic responsivity and/or presynaptic release from neurons containing other neurotransmitters. They also indicate, however, that muOR agonists directly affect a small population of dopaminergic neurons expressing muOR on their dendrites in VTA and/or terminals in target regions.

Mu-opioid receptors in the ventral tegmental area are targeted to presynaptically and directly modulate mesocortical projection neurons

Mesocorticolimbic projections originating from dopaminergic and GABAergic neurons in the ventral tegmental area (VTA) play a critical role in opiate addiction. Activation of mu-opioid receptors (MOR), which are located mainly within inhibitory neurons in the VTA, results in enhanced dopaminergic transmission in target regions, including the medial prefrontal cortex (mPFC). We combined retrograde tract-tracing and electron microscopic immunocytochemistry to determine if neurons in the VTA that project to the mPFC contain MOR or receive input from MOR-containing terminals. Rats received unilateral injections of the retrograde tracer Fluoro-Gold (FG) into the mPFC. Tissue sections throughout the VTA were then processed for electron microscopic examination of FG and MOR. Immunoperoxidase labeling for FG was present in VTA cell bodies that contained immunogold-silver particles for MOR that often were contacted by profiles exclusively immunoreactive for MOR, including somata and axon terminals. The majority of dually labeled profiles were dendrites that received convergent input from unlabeled axon terminals forming either symmetric or asymmetric type synapses. Within retrogradely labeled cell bodies and proximal dendrites, MOR immunoreactivity was mainly sequestered within the cytoplasm. In contrast, distal retrogradely labeled dendrites contained MOR gold particles located along the plasma membranes. These data suggest that opiates active at MOR in the VTA modulate cortical activity through 1) presynaptic actions on MOR in terminals contacting mesocortical cell bodies, and 2) direct activation of MOR in distal dendrites of projection neurons.

Dendritic and axonal targeting of the vesicular acetylcholine transporter to membranous cytoplasmic organelles in laterodorsal and pedunculopontine tegmental nuclei

Autoregulation of cholinergic neurons in the laterodorsal tegmental (LDT) and pedunculopontine (PPT) nuclei has been implicated in many functions, most importantly in drug reinforcement and in the pathophysiology of schizophrenia. This autoregulation is attributed to the release of acetylcholine, but neither the storage or release sites are known. To determine these sites, we used electron microscopy for the immunocytochemical localization of antipeptide antiserum raised against the vesicular acetylcholine transporter (VAchT) that is responsible for the uptake of acetylcholine into storage vesicles. The cellular and subcellular distribution of VAchT was remarkably similar in the two regions by by using each of two methods, immunogold and immunoperoxidase. In both PPT and LDT nuclei, VAchT labeling was seen mainly on membranous organelles including the trans-Golgi network in many somata. VAchT-immunoreactive tubulovesicles resembling saccules of smooth endoplasmic reticulum were often seen near the plasma membrane in dendrites. The VAchT-containing dendrites comprised almost 50% of the labeled profiles (1027/2129) in PPT and LDT nuclei. The remaining VAchT-immunoreactive profiles were primarily small unmyelinated axons and axon terminals. In axon terminals, VAchT was densely localized to membranes of small synaptic vesicles. The VAchT-immunoreactive axon terminals formed either symmetric or asymmetric synapses. The postsynaptic targets of these axon terminals included dendrites that were with (36/110) or without (74/110) VAchT immunoreactivity. Our results suggest that dendrites, as well as axon terminals, have the potential for storage and release of acetylcholine in the LDT and PPT nuclei. The released acetylcholine is likely to play a major role in autoregulation of mesopontine cholinergic neurons.

Cholinergic axon terminals in the ventral tegmental area target a subpopulation of neurons expressing low levels of the dopamine transporter

Cholinergic activation of dopaminergic neurons in the ventral tegmental area (VTA) is thought to play a major role in cognitive functions and reward. These dopaminergic neurons differentially project to cortical and limbic forebrain regions, where their terminals differ in levels of expression of the plasmalemmal dopamine transporter (DAT). This transporter selectively identifies dopaminergic neurons, whereas the vesicular acetylcholine transporter (VAchT) is present only in the neurons that store and release acetylcholine. We examined immunogold labeling for DAT and immunoperoxidase localization of VAchT antipeptide antisera in single sections of the rat VTA to determine whether dopaminergic somata and dendrites in this region differ in their levels of expression of DAT and/or input from cholinergic terminals. VAchT immunoreactivity was prominently localized to membranes of small synaptic vesicles in unmyelinated axons and axon terminals. VAchT-immunoreactive terminals formed almost exclusively asymmetric synapses with dendrites. Of 159 dendrites that were identified as cholinergic targets, 35% contained plasmalemmal DAT, and 65% were without detectable DAT immunoreactivity. The DAT-immunoreactive dendrites postsynaptic to VAchT-labeled terminals contained less than half the density of gold particles as seen in other dendrites receiving input only from unlabeled terminals. These results suggest selective targeting of cholinergic afferents in the VTA to non-dopaminergic neurons and a subpopulation of dopaminergic neurons that have a limited capacity for plasmalemmal reuptake of dopamine, a characteristic of those that project to the frontal cortex.

Sleep patterns after carbachol delivery in the ventral oral pontine tegmentum of the cat

This study examines dose-related effects on sleep produced by low-volume and low-dose carbachol microinjections in the ventral part of the cat nucleus reticularis pontis oralis. Carbachol microinjections (0.04, 0.08, 0.8 or 4 microg; volume 20 nl) in this location triggered paradoxical sleep with a very short dose-unrelated latency. The four carbachol doses effectively generated all the polygraphic and behavioral signs of paradoxical sleep when microinjected at any level within the ventral part of the nucleus reticularis pontis oralis (AP 0.5 to -3.5, L 0.5-3.5, V 3.5-5.0, on the Reinoso-Suárez atlas [Topographischer Hirnatlas der Katze (1961); Merck, Darmstadt]). The dose-related increase of total paradoxical sleep time was due to the increase in both the duration and number of paradoxical sleep episodes. This paradoxical sleep increase was associated with a dose-related decrease in the amount of time spent in both slow wave sleep and drowsiness, but not with any decrease in total wakefulness. The lengthening of the latency to slow wave sleep onset was dose related. These results show that the ventral oral pontine tegmentum is a very sensitive site for the induction and maintenance of paradoxical sleep.

Neocortical and hippocampal electrical activities are similar in spontaneous and cholinergic-induced REM sleep

Neocortical and hippocampal EEG power spectra obtained during REM-like sleep induced by unilateral carbachol microinjections (0.01 M, 0.02 M and 0.2 M; volume 20 nl) into the ventral part of the nucleus reticularis pontis oralis have been compared with EEG power spectra obtained during spontaneous REM sleep. Our findings indicate that neocortical and hippocampal electrical activities during the REM-like state generated by carbachol delivery in this pontine region mimic those present in spontaneous REM sleep.

Opiate microinjections in the locus coeruleus area of the cat enhance slow wave sleep

The effects on sleep/wakefulness states of morphine, morphiceptin (specific mu agonist), DPDPE (delta agonist) and U-50,488H (kappa agonist) microinjections in the Locus coeruleus area (LC) were studied in cats. Morphine (0.8-1.75 nmols in 50 nl of saline) and morphiceptin (1.75 nmols) in LC significantly increased the total time spent in slow wave sleep (SWS) and the mean duration of SWS episodes. Prior naloxone administration blocked the morphine hypnogenic effects. The total time spent in SWS was unaffected by delivery of equimolar doses of DPDPE or U-50,488H in LC; however, the mean duration of the SWS episodes increased significantly after U-50,488H microinjections in LC. Thus, when acting in the LC, opiates have a SWS-enhancing effect and this effect appears to be mediated by mu receptors, although kappa receptors may have a subsidiary action.