ISSN:0887-4476    

DOI:10.1002/syn.890020302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAn attempt is made to deal with the complexity of the nerve fibers in the median eminence. Visual aids are presented in the shape of “wheels” that depict a dynamic interplay of neurochemicals which result in the release of hormones from the anterior pituitary gland. The multiplicity of neurochemicals in the median eminence is perceived to be responsible for the integrated control of pituitary hormone releasing fact

ISSN:0887-4476    

DOI:10.1002/syn.890020303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractPeptides derived from pro‐opiomelanocortin (POMC) influence neurodevelopmental processes. Earlier studies indicated that MSH/ACTH compounds improved behavioral efficiency in retarded individuals. Recent studies have shown that opiate blockers reduce treatment‐resistant self‐injurious behavior (SIB), an autistic‐like, developmental disorder. Although the exact mechanisms are unknown, prenatal POMC disregulation, addiction to endogenous opiates and elevated pain threshold have been proposed to account for this behavior. In study one, four SIB patients were given 0, 25, 50 or 100 mg of naltrexone on separate weeks in a double blind, Latin square design. A specific dose dependent reduction in SIB was observed in three patients. In study two, plasma b‐endorphin was measured in 40 patients with SIB, a related behavior, stereotypy (ST) or controls. SIB and ST patients had higher levels of endorphin than controls. These data added new support for the role of b‐endorphin in a treatment‐resistant

ISSN:0887-4476    

DOI:10.1002/syn.890020304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe neuropeptide ACTH 4–10, a nonsteroidogenic fragment of adrenocorticotropic hormone, has two distinct and opposite effects on developing nerve and muscle. Muscle is positively influenced by ACTH during the first part of gestation (G days 3–12) before innervation occurs. Subsequent effects on innervation are largely depressive and exerted only during G13–21. Treatment during G3–12 increases twitch amplitude, rise time and speed of contraction of directly and indirectly stimulated extensor digitorum longus (EDL) muscle of two wk old rats. Treatment during G13–21 slows contractions of indirectly stimulated EDL, whereas treatment throughout gestation (G3–G21) shows little effect. Thus, ACTH first accelerates muscle development then modulates this development through neuronal

ISSN:0887-4476    

DOI:10.1002/syn.890020305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe ability of d(CH2)5‐Tyr(Me)‐arginine‐8‐vasopressin, an antagonist of peripheral pressoric (V1‐type) vasopressin receptors, to label vasopressin binding sites in the septum of the rat brain was evaluated. Using crude membrane preparations from the septum,3H‐arginine‐8‐vasopressin (AVP) specifically labels a single class of binding sites with a Kdof 2.9nM and maximum binding site concentration of 19.8 fmole/mg protein.3H‐Antag also labels a single class of membrane sites but with higher affinity (Kd=0.47nM) and lower capacity (10.1 fmole/mg protein) than3H‐AVP. The rank order of potency of various competitor peptides for3H‐AVP and3H‐Antag binding was similar. Oxytocin was 100–1,000 fold less potent than AVP in competing for binding with both ligands.3H‐AVP and3H‐Antag showed similar labeling patterns when incubated with septal tissue slices. Unlabeled Antag also effectively antagonized vasopressin‐stimulated phosphatidylinositol hyd

ISSN:0887-4476    

DOI:10.1002/syn.890020306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIt is now known that various growth factors may also act in the central nervous system. Among them, it has recently been shown that epidermal growth factor (EGF) and insulin‐like growth factor I (IGF‐I) may possess trophic effects in the mammalian brain. We report here on the respective autoradiographic distribution of [125I]EGF and [125I]IGF‐I receptor binding sites in the rat brain, both during ontogeny and in adulthood. It appears that [125I]IGF‐I sites are more widely distributed both during ontogeny and in adulthood. These results reveal the plasticity of the expression of EGF and IGF‐I receptor sites in the mammalian brain. This could be relevant for the respective role of these two growth factors in the development and maintenance of neuronal

ISSN:0887-4476    

DOI:10.1002/syn.890020307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe motor neurons for the accessory muscles of respiration, pectoralis, trapezius, external oblique, and the rectus abdominis were studied in the spinal cord. The objective was to determine if the localization and morphology of the motor neurons for these muscles bear any distinct relationship to the specialized function of these muscles, serving both as supportive skeletal muscles and as accessory respiratory muscles. In addition, it was of interest to know if the inspiratory role of the pectoralis and trapezius muscles and the expiratory role of the external oblique and rectus abdominis are related to the spatial organization of the motor neurons; this knowledge may be important in the discrimination of influences from afferent connections. The motor neurons for these muscles were retrogradely labeled with true blue and were compared with the triceps motor neurons. All neurons occurred ipsilateral and most labeling occurred in C6–7. The motor neurons for the accessory muscles were mainly confined to the ventrolateral tip of the ventral gray matter. The triceps neurons were dorsolateral to the respiratory related neurons in C6–7. Within the confines of the ventrolateral area, the majority of neurons for the pectoralis were localized medial to ventromedial, those for the trapezius were ventrolateral, and those for the external oblique were in the extreme ventrolateral to ventral sections of C7. No neurons were observed in C2 to T2 for the rectus abdominis. A second neuronal column occurred medioventrally in the ventral gray of C4–6 for the trapezius, and is distinct and separated from the C6–7 cell column. The motor neurons for the accessory muscles were oval in shape and of medium size (≈︁ 35 microns). Those for the triceps were small to large 18–45 microns, elongated in shape with distinctly labeled processes and well defined perimeter. The neurons within each column often occurred in clumps and are probably separated by densely packed dendrites that may cause the insulation of one cellular column from another to achieve discriminatory afferent influences to individual neuronal columns. The localization of the motor neurons for the accessory respiratory muscles in C7 superimposed the localization of a high density of substance P receptors (Charlton and Helke, 1986) that also occurred in the phrenic nucleus. The overlapping of the substance P receptors with the motor neurons for the accessory respiratory muscles is supportive of a role for substance P in respiratory control. Finally, the accesory respiratory muscles were innervated by dorsal root sensory neurons that occurred throughout the cervical segments and the first and second thoracic segments. This was in contrast to the innervation of the triceps by sensory neurons located in just one or two segments from its motor neurons o

ISSN:0887-4476    

DOI:10.1002/syn.890020308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn a previous study of afferent projections to the nucleus tractus solitarii (NTS), it was shown that over half of the retrogradely‐labelled neurons in the nucleus raphe pallidus contained serotonin‐immunoreactivity and over half of these neurons contained substance P‐immunoreactivity, suggesting that these two putative neurotransmitters are colocalized in NTS‐affent neurons. The objectives of the present study were to (1) directly determine if varicosities in the NTS, the area postrema (AP), and the dorsal motor nucleus of the vagus nerve (DMN) do contain both transmitters, (2) determine if primary afferent neurons in the nodose and petrosal ganglia might also colocalize serotonin and substance P, and (3) quantify the amount of substance P that is contained in serotonergic varicosities in the NTS.Distributions and colocalization of substance P and serotonin in the NTS were studied using dual‐color immunohistochemistry, while the quantity of substance P in serotonergic varicosities was assessed by radioimmunoassay (RIA) using micropunches from the NTS of 5,7‐dihydroxytryptamine‐(5,7 DHT—) and vehicle‐treated rats.Varicosities that contained both serotonin‐ and substance P‐immunoreactivity were found in the NTS, the DMN, and the AP. Double‐labelled varicosities were common in the NTS and DMN (i.e., qualitatively similar to the density seen in the hypoglossal nucleus and in the ventral horn of the cervical spinal cord); however, the vast majority of the varicosities in these autonomic areas only displayed immunoreactivity for one or the other of these transmitters.This paucity of doubly‐labelled varicosities, in comparison to the number of singlylabelled varicosities, was reflected in the lack of a significant decrease in substance P levels as determined by RIA of micropunches taken from caudal and intermediate levels of the NTS in 5,7 DHT—and vehicle‐treated rats. At rostral levels of the NTS, however, there was a significant reduction (45%) in substance P levels in 5,7 DHT‐treated rats compared to vehicle‐treated rats. Immunohistochemical evaluation of sections from the rostral NTS of 5,7 DHT‐treated rats also indicated that the density of substance P varicosities was reduced.Immunohistochemical studies of the nodose and petrosal ganglia showed numerous serotonin‐ and substance P‐immunoreactive neurons, but none of the neurons contained immunoreactivity for both transmitters.In conclusion, serotonin and substance P are colocalized in varicosities in the NTS, the DMN, and the AP. Based upon the absence of primary afferent neurons that exhibit colocalization of serotonin and substance P, and previous studies of serotonin‐ and substance P‐containing NTS‐afferent neurons; it appears that the caudal medullary raphe nuclei are the source of varicosities that colocalize serotonin and substance P. While the density of these varicosities in the NTS and DMN are comparable to the density seen in the ventral horn of the spinal cord, this comprises only a small proportion of the varicosities in the NTS

ISSN:0887-4476    

DOI:10.1002/syn.890020309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWhole mounts of guinea pig ileum submucosa were incubated with radiolabeled tachykinins, and binding sites were visualized using autoradiography. Very dense specific binding for [125I]‐Bolton‐Hunter substance P (BHSP) was observed over ganglia of the submucous plexus, with weaker binding over internodal strands. Dense specific binding was also seen over occasional strands of circular muscle, with weak binding over clumps of mucosa. Although very weak binding was seen over some large blood vessels, no binding was associated with smaller blood vessels. Localization of binding was absent in whole‐mounts coincubated with 1 nM substance P, used to define nonspecific binding. Localization of BHSP‐specific binding was also abolished in whole‐mounts coincubated with 1 nM substance P, but not with 1 nM neurokinin B, suggesting that binding was probably to an NK‐1 tachykinin receptor. In whole‐mounts incubated in [125I]‐iodohistidyl neurokinin A (INKA) or [125I]‐Bolton‐Hunter neurokinin B (BHNKB), no specific binding over ganglia was observed. These binding sites for BHSP are probably identical with the neuronal substance P receptors mediating mu

ISSN:0887-4476    

DOI:10.1002/syn.890020310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to examine the binding and behavioral effects mediated by PCP and sigma receptors in the rat. From the radioreceptor assays, it was possible to characterize two binding sites that interact with PCP and sigma ligands. The two sites, a PCP and sigma receptor, could be differentiated based on drug selectivity and potency. In the behavioral assays, MK‐801, which bound preferentially to the PCP receptor, and 1,3‐di‐O‐tolylguanidine, which bound preferentially to the sigma receptor, induced sniffing, rearing, circling, backpedaling, and weaving behavior. These results indicate that there are distinct PCP and sigma receptors that are both involved in mediating stereotyped behavior and ataxia in

ISSN:0887-4476    

DOI:10.1002/syn.890020311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY