Effect of peripheral administration of arginine vasotocin on neonatal sleep in rats

Characterization and distribution of an arginine vasotocin receptor in mouse

A cDNA, which has a high homology with teleost Platichthys flesus [Arg8] vasotocin (AVT) receptor (GenBank: AK033957), was found in mouse genome database. Analyses of the deduced amino acid sequence revealed that a cDNA has several features of AVT receptor. We tentatively named it as a mouse vasotocin receptor (MVTR). A two-electrodes voltage clamp technique was applied to characterize the MVTR expressed in Xenopus laevis oocytes. AVT induced Ca2+-dependent Cl- currents in Xenopus oocytes injected with MVTR cRNA. On the other hand, [Arg8] vasopressin, oxytocin and isotocin did not induce such currents. RT-PCR showed that MVTR mRNA was specifically expressed in the brain. In situ hybridization analysis demonstrated significant expression of MVTR mRNA in suprachiasmatic nucleus, arcuate nucleus and medial habenular nucleus of mouse brain. These results suggest that MVTR may mediate a variety of physiological functions in mouse.

Effects of peptides on animal and human behavior: a review of studies published in the first twenty years of the journal Peptides

This review catalogs effects of peptides on various aspects of animal and human behavior as published in the journal Peptides in its first twenty years. Topics covered include: activity levels, addiction behavior, ingestive behaviors, learning and memory-based behaviors, nociceptive behaviors, social and sexual behavior, and stereotyped and other behaviors. There are separate tables for these behaviors and a short introduction for each section.

The effects of REM sleep-inhibiting drugs in neonatal rats: evidence for a distinction between neonatal active sleep and REM sleep

Neonatal active sleep (AS) has been considered to be homologous and continuous with rapid-eye-movement (REM) sleep in adult animals. We have recently proposed an alternative view that AS is an undifferentiated sleep state distinct from REM sleep. To test these opposing views on the relationship of AS and REM sleep, neonatal rats (P11, P14 and P20) were systemically injected with compounds that inhibit REM sleep in adults. Zimelidine (ZMI) and desipramine (DMI) are monoamine uptake inhibitors which increase synaptic concentrations of serotonin and norepinephrine, respectively. Serotonin and norepinephrine inhibit brainstem cholinergic neurons important in REM sleep generation. Atropine (ATR) is a muscarinic receptor antagonist that blocks the post-synaptic effects of cholinergic projections. Only DMI (5 mg/kg) suppressed AS at P11. ZMI (6 mg/kg) and ATR (6 mg/kg) did not suppress AS until P14. These data suggest that serotonergic and cholinergic regulation of AS are absent before P14. The fact that AS in P11 rats is not affected by cholinergic antagonists supports the hypothesis that AS and REM sleep represent different sleep states.

Mechanisms of the antihypertensive effects of dietary calcium and role of calcitonin gene related peptide in hypertension

Alterations in calcium metabolism and calcium-regulating hormones have been described in essential hypertension. However, the mechanisms that mediate these responses are unknown. In previous studies, using the genetically spontaneously hypertensive rat and the mineralocorticoid-salt (DOC-salt) hypertensive rat model, we and others have observed that oral calcium supplementation attenuates the associated increase in peripheral vascular resistance and consequently lowers blood pressure (BP). When hypertensive patients (n = 8, diastolic BP 90-95 mmHg (1 mmHg = 133.3 Pa)) were given daily oral calcium supplementation (1.4 g elemental calcium), both systolic and diastolic BP were decreased (5-10 mmHg, p < 0.01). The only biochemical variables significantly changed were serum ionized calcium and intact parathyroid hormone (PTH, 1-84) (p < 0.05); furthermore, the levels of calcitonin gene related peptide (CGRP), measured by both radioimmunoassay and radioreceptor assay, showed a marked 75% increase (p < 0.001). The antihypertensive effects of Ca2+ and the increased levels of CGRP in the circulation returned to baseline levels immediately following cessation of calcium supplementation, suggesting that the effects of calcium on BP and CGRP are specific. On the basis of these observations were proposed that the antihypertensive effect of dietary calcium supplementation, at least in part, is mediated through CGRP.

CNS effects of peptides: a cross-listing of peptides and their central actions published in the journal Peptides, 1986-1993

The centrally mediated effects of peptides as published in the journal Peptides from 1986 to 1993 are tabulated in two ways. In one table, the peptides are listed alphabetically. In another table, the effects are arranged alphabetically. Most of the effects observed after administration of peptides are grouped, wherever possible, into categories such as cardiovascular and gastrointestinal. The species used in most cases has been rats; where other animals were used, the species is noted. The route of administration of peptides and source of information also are included in the tables, with a complete listing provided at the end. Many peptides have been shown to exert a large number of centrally mediated effects.

Vasotocin increases quiet sleep and suppresses active sleep in newborn cats. Opposite effects after vasotocin immunoneutralization

One picogram of synthetic arginine vasotocin (AVT) administered into the lateral ventricle of newborn cats aged 7-9 days, increased the amount of quiet sleep and markedly decreased the amount of active sleep. Ten pg AVT completely suppressed active sleep during the recording time of 3 hr. The increase in the quiet sleep occurred within 5-7 min and lasted for the entire recording time of 3 hr. An undiluted specific AVT antiserum (10 microliters) administered into the lateral ventricle, induced opposite effects suppressing quiet sleep and increasing active sleep. It is concluded that in newborn cats both AVT and the AVT antiserum induce the same hypnogenic effects as in the adult cats.