Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity profiles of homozygous tau mutant hamsters bred in our colony exhibit several differences when compared to wildtype golden hamsters. In addition, tau mutant hamsters respond to saturating white light pulses presented between circadian time (CT) 11 and CT 16 with extremely large phase shifts (type 0 resetting) after prolonged time in constant darkness. We measured five parameters of the activity rhythm early during exposure to constant darkness (DD) (cycles 5-9), and after 44-48 cycles in DD, and we confirmed the tau mutants' unusual phase shifting response to light. Next we determined whether neurotransmitter peptide mRNA levels in the SCN differed between wildtype and tau mutant hamsters exhibiting these divergent activity patterns and responses to light. After 49 circadian cycles in DD, tau mutant hamsters responded to a 1 h light pulse at CT 15 with phase shifts averaging 10.19 +/- 0.35 h. Among wildtype hamsters the mean phase shift was 1.22 +/- 0.34 h and the largest phase shift observed was 3.67 h. Total wheel revolutions/circadian cycle were significantly lower in tau mutants (4022 +/- 1103) vs. wildtypes (7528 +/- 458) and there was a significant decrease in wheel-running activity after prolonged exposure to DD, particularly among the wildtype hamsters (tau = 3045 +/- 972, wildtype = 4362 +/- 388 rev/circadian cycle). When analyzed by 5 min segments throughout the circadian cycle, the highest intensity wheel-running activity did not differ between groups and there was no significant effect of length of time in DD on this measure (tau = 38.5 +/- 6.3 and 38.4 +/- 4.7 rev/min, wildtype = 46.8 +/- 1.7 and 41.4 +/- 2.7 rev/min early or late in DD, respectively). The precision of activity onset differed greatly between groups with tau mutants exhibiting a much higher daily deviation from mean tau (1.00 +/- 0.24 h) than wildtypes (0.14 +/- .02 h). Activity onset became significantly less precise with increased time in DD: tau = 1.66 +/- 0.21 h, wildtype = 0.45 +/- 0.14 h after 44-48 circadian cycles. The length of the active period, alpha, was significantly shorter in tau mutants than in wildtypes (7.2 +/- 0.2 h vs. 8.0 +/- 0.2 h) but alpha was a similar percentage of tau in the two groups (tau mutant = 36%, wildtype = 33%). After 48 circadian cycles in DD, alpha measured 7.2 +/- 0.5 h in tau mutants and 8.9 +/- 0.6 h in wildtypes, thus there was no significant effect of time in DD on this parameter. Activity records of tau mutant animals appear more fragmented to the eye and we quantitated this with a computer-aided analysis of the number of bouts of wheel-running per active period. Wildtype hamsters exhibited 2.8 +/- 0.2 bouts of wheel-running activity early in DD and 3.1 +/- 0.2 bouts per circadian cycle later in DD. The activity records of tau mutant hamsters were significantly more fragmented but this group actually showed some consolidation of bouts per circadian cycle after prolonged time in DD (4.7 +/- 0.3 vs. 3.9 +/- 0.3 bouts per cycle). Wildtype and tau mutant hamsters were killed after 66-71 cycles in DD at either CT 4 or CT 16 and in situ hybridization was performed for vasopressin (AVP) and vasoactive intestinal peptide (VIP). Levels of AVP and VIP mRNA were significantly lower in tau mutant than wildtype hamsters at CT 16. We conclude that the tau mutation causes these differences in gene expression and we speculate that differences in the peptidergic output of the clock may have some relevance for the differences in the quantitative aspects of the activity rhythm and the response to light pulses exhibited by these animals.
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PMID:Quantitative differences in the circadian rhythm of locomotor activity and vasopressin and vasoactive intestinal peptide gene expression in the suprachiasmatic nucleus of tau mutant compared to wildtype hamsters. 893 Mar 31

The purpose of this study was to characterize the role of M2 muscarinic receptors in inhibiting relaxant effects of drugs that stimulate cyclic AMP (cAMP) accumulation in the guinea pig ileum. We investigated the ability of oxotremorine-M (oxo-M) to inhibit cAMP accumulation in the presence of agonists that stimulate adenylyl cyclase in other cells and tissues. Appreciable stimulation of cAMP (> 50% over basal levels) was achieved with forskolin and maximally effective concentrations of isoproterenol, cicaprost, prostaglandin E1, prostaglandin E2 and prostaglandin I2, with the stimulation over basal levels of cAMP being 14.9-, 2.51-, 2.45-, 2.27-, 2.28- and 1.52-fold, respectively. Moderate or no cAMP stimulation was observed with dopamine, 5-hydroxytryptamine, 5-methoxytryptamine, dimaprit, vasoactive intestinal peptide, SKF-38393, 2-chloroadenosine, CGS-21680, prostaglandin D2, secretin and vasopressin. Oxo-M (1 microM) inhibited cAMP accumulation by 35% under basal conditions. Oxo-M inhibited specific agonist-stimulated cAMP levels by 20 to 70%. However, oxo-M caused little or no inhibition of specific prostaglandin I2- and cicaprost-stimulated cAMP levels (5 and 0%, respectively). In general, there was a correlation between the abilities of the various agonists to stimulate cAMP accumulation and to cause relaxation of the isolated ileum, with an exception being cicaprost. Experiments were carried out with isolated ileum to determine whether activation of M2 receptors inhibited the relaxant effects of the various agonists. In these experiments, the ileum was first treated with N-(2-chloroethyl)-4-piperidinyl diphenylacetate to selectively inactivate M3 receptors. After this treatment phase, contractile responses to oxotremorine-M were measured in the presence of histamine and a given relaxant agent. These measurements were repeated in the presence of the M2-selective antagonist AF-DX 116. Analysis of the data showed that part of the contractile response to oxotremorine-M could be attributed to an M2-mediated inhibition of the relaxation. This M2 component of the contractile response was greatest when forskolin or isoproterenol was used as the relaxant agent. In contrast, little or no M2 response was measured in the presence of dopamine and cicaprost.
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PMID:M2 muscarinic receptor inhibition of agonist-induced cyclic adenosine monophosphate accumulation and relaxation in the guinea pig ileum. 899 96

Light- and electron-microscopic immunocytochemistry was used to investigate grafts of foetal hypothalamic tissue implanted close to the site of the suprachiasmatic nucleus in adult rats with bilateral surgical ablation of this nucleus. The transplants contained vasoactive intestinal peptide and vasopressin cell clusters, which have previously been shown to characterize functional suprachiasmatic nucleus grafts. Vasoactive intestinal peptide and vasopressin neurons presented synaptic features that have not been described in the native suprachiasmatic nucleus. More specifically, their terminals within the graft were involved in 'double' synapses with separate unlabelled dendrites. Moreover, in dually stained sections, an unexpected synaptic investment of vasoactive intestinal peptide neurons by vasopressin endings was detected, which revealed reversed vasoactive intestinal peptide/vasopressin interactions compared to those described in the native nucleus. These observations could reflect some immature features of the grafted neurons. Ultrastructural relationships of monoaminergic fibres arising from host and/or intragraft neurons were also examined. Within the engrafted suprachiasmatic nucleus, tyrosine hydroxylase-labelled fibres, which probably belonged to cografted dopaminergic neurons, showed normal patterns of distribution and synaptic connections, with no preferential relationships with vasoactive intestinal peptide or vasopressin neurons. Serotoninergic axons arborized within transplants but, in agreement with previous data showing an inhibitory influence of the suprachiasmatic nucleus on ingrowing serotoninergic fibres, they had no predilection for the area corresponding to that nucleus. In spite of their relative scarcity, serotoninergic fibres within the engrafted suprachiasmatic nucleus showed an almost normal synaptic incidence, but synapses were not predominantly shared with the vasoactive intestinal peptide neurons, known to be their major targets in the native nucleus. This may contribute not only to the failure of functional grafts to synchronize with environmental conditions, but also to the inability of transplants to restore hormonal rhythms such as estrous cyclicity.
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PMID:Intrinsic organization and monoaminergic innervation of the suprachiasmatic nucleus transplanted to adult rats. A light- and electron-microscopic study. 901 27

The suprachiasmatic nucleus (SCN) is critically involved in the generation and entrainment of circadian rhythms in mammalian species. Both the occurrence and the timing of the luteinizing hormone surge on the afternoon of proestrus in the female rodent are critically dependent on the integrity of the SCN. Recently, we demonstrated the presence of a monosynaptic pathway from the SCN to the gonadotropin releasing hormone (GnRH) neurons in the preoptic area. In addition, we found that interaction between the SCN and the GnRH system may be found close to the SCN, since we observed apposition of SCN efferents and GnRH fibers at the ultrastructural level in that region. The aim of the present study was to investigate the presence of synaptic contacts between GnRH fibers and structures in the SCN and surrounding perichiasmatic area (periSCN). At the light microscopical level, the immunoreactivity for GnRH showed a considerable overlap with the immunoreactivity for vasopressin and vasoactive intestinal peptide, two neuropeptides synthesized by SCN neurons. At the ultrastructural level, we demonstrated synaptic input of GnRH-containing axons on immunocytochemically unidentified structures in the SCN/peri-SCN region. The present results clearly demonstrate that the SCN and periSCN are postsynaptic targets of GnRH fibers. It is hypothesized that the GnRH input in the SCN region represents an anatomical substrate for feedback-control between these systems.
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PMID:Synaptic contacts between gonadotropin-releasing hormone-containing fibers and neurons in the suprachiasmatic nucleus and perichiasmatic area: an anatomical substrate for feedback regulation? 916 45

The morphological interactions between astroglial and neuronal elements were elucidated in the rat suprachiasmatic nucleus (SCN) by light and electron microscopic immunocytochemistry using antibodies against glial fibrillary acidic protein (GFAP), vasoactive intestinal peptide (VIP) and arginine-vasopressin (AVP). Throughout the SCN, particularly in its ventral portion, GFAP-like-immunoreactive (GFAP-LI) astroglial elements were found. These astrocytes displaying GFAP-like immunoreactivity occasionally contained fairly well-developed organelles. Some of these astrocytes were found as satellite cells in close contact with non-immunoreactive neuronal perikarya and processes. Around the neurons, GFAP-LI astroglial processes were also observed to cover some portions of presynaptic and postsynaptic elements. In addition, these astroglial elements were seen between two neuronal somata and pericytes of blood capillaries as glial endfeet. By double labeling immunoelectron microscopy using antibodies against GFAP/VIP and GFAP/AVP, some portions of VIP-like-immunoreactive or AVP-like-immunoreactive neuronal somata and processes were found to be engulfed by GFAP-LI astroglial processes. The possible functional roles of the morphological interactions between astroglial and neuronal elements are discussed.
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PMID:Neuron-glia interaction in the suprachiasmatic nucleus: a double labeling light and electron microscopic immunocytochemical study in the rat. 951 Apr 20

Rhythms in the expression of the nuclear phosphoprotein Fos, have been demonstrated in the suprachiasmatic nucleus (SCN) of nocturnal rodents. When rats are housed in a 12:12-h light/dark (LD) cycle the number of Fos-immunoreactive (-IR) cells within the SCN is higher during the day than at night [9,23]. In the two experiments reported here, Fos-IR was examined in the SCN of a diurnal murid rodent, Arvicanthis niloticus. First, thirty-six adult male A. niloticus housed in a 12:12-h LD cycle were perfused at six equally spaced time points beginning 1 h after lights on (n=6 per time point). Brains were sectioned and treated with immunohistochemical procedures for the identification of Fos. The number of Fos-IR cells in the SCN varied significantly as a function of time, and was highest 1 h after lights on and decreased thereafter. The distribution of Fos-IR within the SCN overlapped with that of arginine-vasopressin-IR (AVP-IR) and vasoactive intestinal peptide-IR (VIP-IR), but not with that of gastrin-releasing peptide-IR (GRP-IR). In the second study, double-labeling techniques revealed extensive Fos expression within SCN neurons containing AVP-IR, but not neurons containing GRP-IR. In conclusion, although the overall rhythm of Fos-IR in the SCN is similar in diurnal and nocturnal rodents, differences may exist with respect to the relative distribution of Fos-immunoreacte cells within different SCN cell populations.
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PMID:The expression of Fos within the suprachiasmatic nucleus of the diurnal rodent Arvicanthis niloticus. 959 11

Seasonal changes in daylength (photoperiod) affect many aspects of mammalian physiology and behavior, including reproduction, metabolism, thermoregulation, and sleep. The circadian pacemaker in the hypothalamic suprachiasmatic nuclei (SCN) regulates these photoperiodic changes. Our studies of the Siberian hamster SCN have shown that two types of neuropeptide-containing neurons, vasopressin (AVP) and vasoactive intestinal peptide (VIP) neurons, respond to short photoperiod by decreasing mRNA expression. The present studies investigated whether photoperiodic inhibition of mRNA expression also occurs in somatostatin-synthesizing neurons in the SCN, depends upon the pineal gland, and occurs in neurons in other hypothalamic nuclei. Juvenile Siberian hamsters exposed to either long photoperiod (16 h light/day) or short photoperiod (10 h light/day) for 2 weeks after weaning, were used for these studies. Coronal sections throughout the SCN were prepared and processed for in situ hybridization. The results showed that photoperiod decreased the expression of AVP mRNA and VIP mRNA in the SCN, as seen previously, but not somatostatin mRNA. Furthermore, pinealectomy did not attenuate the short photoperiod inhibition of AVP mRNA and VIP mRNA expression in the SCN. Also, short photoperiod inhibition of AVP mRNA expression was found in the paraventricular and supraoptic nuclei, as well as in the SCN. These results show that short photoperiod inhibition of mRNA expression is partially selective among the neuropeptides, but is not restricted to the SCN. Furthermore, these findings suggest that photoperiodic regulation of neuropeptide mRNA expression is independent of pineal melatonin secretion and gonadal steroid secretion.
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PMID:Photoperiodic regulation of hypothalamic neuropeptide messenger RNA expression: effect of pinealectomy and neuroanatomical location. 963 May 80

To examine the roles of Arg-vasopressin (AVP)- and vasoactive intestinal peptide (VIP)-containing neurons in the suprachiasmatic nucleus (SCN) in production of circadian rhythmicity of locomotor activity, variations in the contents of AVP and VIP in punched-out SCN tissue and locomotor activity were measured under a light-dark cycle as well as under conditions of constant light for up to 3 weeks. Under the light-dark cycle, contents of AVP and VIP, and locomotor activity showed marked circadian rhythmicity. Under constant light, AVP content showed circadian rhythmicity until 3 weeks, while VIP rhythm disappeared from the first week with decreases in its content. Locomotor activity showed a free-running circadian rhythm for more than 3 weeks under constant light conditions in most cases. These results suggest that AVP but not VIP in the SCN may be involved in the generation of locomotor activity rhythm under conditions of constant light.
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PMID:AVP rhythm in the suprachiasmatic nucleus in relation to locomotor activity under constant light. 966 47

We have studied melatonin effects on vasopressin release from dispersed cells of the rat suprachiasmatic nuclei (SCN). The release follows a circadian rhythm peaking during the day and decreasing at night. Melatonin inhibits the spontaneous increase and accelerates the decrease of vasopressin release. Melatonin also inhibits vasopressin release induced by vasoactive intestinal peptide (EC50=0.4 nM). The inhibition of vasopressin release correlates with the known inhibitory effect of melatonin on spontaneous neuronal activity in SCN.
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PMID:Melatonin inhibits spontaneous and VIP-induced vasopressin release from suprachiasmatic neurons. 972 96

In view of mounting evidence that the suprachiasmatic nucleus (SCN) is directly involved in the setting of sensitivity of the adrenal cortex to ACTH, the present study investigated possible anatomical and functional connections between SCN and adrenal. Transneuronal virus tracing from the adrenal revealed first order labelling in neurons in the intermedio-lateral column of the spinal cord that were shown to receive an input from oxytocin fibres and subsequently second-order labelling in neurons of the autonomic division of the paraventricular nucleus. The latter neurons were shown to receive an input from vasopressin or vasoactive intestinal peptide (VIP) containing SCN efferents. The true character of this SCN input to second-order neurons was also demonstrated by the fact that third-order labelling was present within the SCN, vasopressin or VIP neurons. The functional presence of the SCN-adrenal connection was demonstrated by a light-induced fast decrease in plasma corticosterone that could not be attributed to a decrease in ACTH. Using intact and SCN-lesioned animals, the immediate decrease in plasma corticosterone was only observed in intact animals and only at the beginning of the dark period. This fast decrease of corticosterone was accompanied by constant basal levels of blood adrenaline and noradrenaline, and is proposed to be due to a direct inhibition of the neuronal output to the adrenal cortex by light-mediated activation of SCN neurons. As a consequence, it is proposed that the SCN utilizes neuronal pathways to spread its time of the day message, not only to the pineal, but also to other organs, including the adrenal, utilizing the autonomic nervous system.
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PMID:Anatomical and functional demonstration of a multisynaptic suprachiasmatic nucleus adrenal (cortex) pathway. 1021 6


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