SEARCH · PubMed Health

Results for “VASOTOCIN”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources

PubMed1992

Evidence of a role for the turkey posterior pituitary in prolactin release.

The aims of this study were: (1) to examine whether the posterior pituitary contains prolactin releasing factor (PRF) activity, (2) to determine to what extent known neurohypophyseal peptides contribute to this activity, and (3) to compare posterior pituitary PRF activities of hens in different reproductive stages. Anterior pituitary cells derived from juvenile female turkeys were incubated with posterior pituitary extracts or test substances for 3 hr. Posterior pituitary extracts (0.1-0.8 equivalent) contained a potent substance(s) which stimulated PRL release in a concentration-dependent manner (2.4 +/- 0.08 to 6.5 +/- 0.23 micrograms/500 k cells). Arginine vasotocin (AVT) and vasoactive intestinal peptide (VIP) antisera (1:500) completely abolished the PRL-releasing activities of their respective peptides but partially reduced (P less than 0.05) the PRF activity of the posterior pituitary (AVT, 19.9%; VIP, 55.1%). Mesotocin antiserum did not alter (P greater than 0.05) PRL release induced by posterior pituitary extract. Posterior pituitary extract (0.01-0.5 equivalent) from hens in each of the various stages of the reproductive cycle induced a concentration dependent PRL release. The 0.5 posterior pituitary equivalent dose from reproductively quiescent (nonphotostimulated), laying, photorefractory, and incubating hens increased PRL release 2.4-, 2.9-, 3.8-, and 11.1-fold, respectively. The turkey posterior pituitary contains a potent PRF activity, partially accounted for by VIP and AVT, at the assayed concentrations, which varies with the reproductive cycle.

Animals↗

PubMed1992

In vitro uterine contractions in the viviparous lizard Tiliqua rugosa: effects of gestation and steroid pretreatment in vivo.

Uterine contractility was investigated in the viviparous lizard Tiliqua rugosa. Arginine vasotocin (AVT) induces rhythmic contractions in vitro in strips of uterine tissue from ovariectomized female T. rugosa. The strength of these contractions was related to the dosage of AVT and reduced by pretreatment in vivo with both progesterone and estradiol-17 beta. The frequency of spontaneous and AVT-induced contractions was enhanced by estradiol-17 beta pretreatment. The strength of AVT-induced contractions in pregnant females was not significantly different from that recorded in nonpregnant females. Spontaneous rhythmic contractions were present only in pregnant females. Ovariectomy did not affect either spontaneous or AVT-induced contractions in pregnant females. The data indicate that ovarian steroids modulate uterine contractility in T. rugosa. It is suggested that, following a decline in plasma progesterone levels, estrogen may be involved in the onset of parturition.

Animals↗

PubMed1992

Localization and quantification of nonapeptide binding sites in the kidney of Xenopus laevis: evidence for the existence of two different nonapeptide receptors.

The distribution and properties of nonapeptide binding sites in the kidney of the anuran Xenopus laevis were investigated using quantitative in vitro autoradiography. The binding studies were performed with [3H]arginine vasopressin (AVP) as ligand because [125I]arginine vasotocin (AVT) lacks biological activity. Specific binding sites for [3H]AVP are located in the glomeruli of the kidney. [3H]AVP binding results in a steady state of association and dissociation between ligand and binding sites. Scatchard and Hill analyses of saturation experiments showed that [3H]AVP binds to a single class of binding sites with a dissociation constant (Kd) of 430 +/- 109 pM and a maximum binding capacity (Bmax) of 5.306 +/- 1.379 fmol/mm2 (n = 8). Displacement studies demonstrated the same affinity of these [3H]AVP binding sites to [3H]AVP, unlabeled AVP, and AVT, whereas mesotocin possesses only weak affinity. Further nonapeptides like oxytocin and isotocin or the mammalian-specific V1 receptor antagonist [1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid)-2-(O-methyl)-tyrosine)-AVP or the V2 receptor agonist (1-deamino-8-D-arginine)-vasopressin or unrelated peptides did not alter the binding of [3H]AVP. The localization of nonapeptide binding sites in the glomeruli with the same affinity to AVP as to AVT agrees with the finding that AVT causes antidiuresis in Xenopus laevis. An earlier study demonstrated Xenopus laevis interrenal tissue to possess a higher sensitivity for AVT than AVP which points to a nonapeptide receptor with a higher affinity for AVT than AVP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Neuroendocrine, behavioral, and morphological changes associated with the termination of the reproductive period in a natural population of male rough-skinned newts (Taricha granulosa).

Male rough-skinned newts (Taricha granulosa) were collected from the same natural population every second week from early April to mid-June. They were either field-tested for their sexual responsiveness or used to measure the plasma concentrations of androgens and corticosterone, the brain concentrations of immunoreactive (ir) gonadotropin-releasing hormone (GnRH) and arginine vasotocin (AVT), and morphological parameters. During the experimental period, the percentage of sexually responsive males gradually declined from 100 to 4%, concurrent with a decrease of plasma concentrations of androgens, but not corticosterone. Concentrations of irGnRH in two brain regions (medial septum; ventral telencephalon containing the nervus terminalis) did not change significantly during this time. In the infundibulum, irGnRH concentrations increased from the end of May to mid-June, which coincided with an increase in plasma androgen concentrations, a marked increase in testis weights, and a decrease of the proportion of males with spermatozoa in their vas deferens. During this period, no changes in irAVT concentrations in four brain regions (infundibulum; pars distalis of the pituitary; interpeduncular nucleus; cerebrospinal fluid) were detected, but significant changes were observed for irAVT in the dorsal preoptic area that were not correlated with the seasonal changes in behavior. Also, during this period, there were decreases in mean body weight and tail height, and in the proportion of males with smooth skin and dark nuptial pads. These results are discussed in view of our current knowledge of the endocrine mechanisms that regulate sexual behaviors and secondary sex characteristics in male amphibians.

Androgens↗

PubMed1985

Comparative effects of prostaglandin E2 and prostaglandin E3 on water flow and cyclic AMP in the urinary bladder of the frog, Rana pipiens.

Prostaglandins (PGs) modulate osmotic water flow in amphibian urinary bladders. Gas chromatographic analysis of prostaglandin precursors in bladders showed that arachidonic acid represented 13.0 +/- 0.6% and eicosapentaenoic acid 4.3 +/- 0.1% of the total fatty acid content. The effects of PGE2 and PGE3 on basal and arginine vasotocin (AVT) stimulated water flow were compared. Control water flow (1.1 +/- 0.2 mg/min) was increased to 4.6 +/- 0.3 mg/min with AVT (10(-6)M) present. PGE2 (10(-6)M) inhibited both basal and AVT stimulated water flow. In contrast, PGE3 (10(-6)M) stimulated basal water flow and further increased AVT stimulated water flow. Basal adenylate cyclase activity (ACA, 59 +/- 0.3 pmol cyclic AMP/mg protein/10 min) was stimulated by the addition of AVT in the absence or presence of exogenous guanosine 5' triphosphate (GTP, 10(-5)M). Both PGE2 and PGE3 stimulated basal ACA in the absence, but not in the presence of GTP. In the absence of exogenous GTP, PGE2 increased AVT stimulated ACA, whereas PGE3 decreased it. Both prostaglandins inhibited AVT stimulation when GTP was added. The effects of PGE2, PGE3 and AVT on tissue cyclic AMP levels in whole urinary bladders were similar to the effects seen on ACA in the absence of exogenous GTP. The contrasting effects of PGE2 and PGE3 on control water flow appear distinct from their similar effects on ACA. However, PGE2 and PGE3 may regulate AVT stimulation through mechanisms involving cyclic AMP.

Adenylyl Cyclases↗

PubMed1983

Neurohypophysial peptides and the hippocampus. II. Excitation of rat hippocampal neurones by oxytocin and vasopressin applied in vitro.

Neurohypophysial peptides were applied by superfusion to rat hippocampal slices. The peptides, arginine vasopressin, lysine vasopressin, arginine vasotocin and oxytocin, increased the activity of 88% of spontaneously active cells in the CA1 region and induced firing in many neurones that were not spontaneously active. The peptide sensitive cells appeared to be pyramidal cells rather than interneurones. The four peptides were found to be of roughly equivalent potency, producing a reversible, dose-dependent response in the range 10(-9) to 10(-6)M. Most of the cells were tested with more than one peptide and were always found to respond either to all or to none of them. The analogue [7-glycine]oxytocin and the deamino, dicarba derivatives of oxytocin and vasopressin were about as active as the parent compounds, but the oxytocin fragment prolyl-leucyl-glycinamide had no effect, and desglycinamide vasopressin was extremely weak. Responses to the peptides could be blocked by "specific" antagonists. The results suggest that all of the peptides are acting upon a single class of receptor.

Animals↗

PubMed1984

Characterization of high affinity binding sites for vasopressin in bovine adrenal medulla.

A crude membrane fraction prepared from bovine adrenal medulla bound tritium labeled arginine-vasopressin (3H-AVP) in a time and temperature dependent manner. Physiological concentrations of Mg2+ (1-3 mmol/l) were required for the binding reaction, while Ca2+ (5-80 mmol/l) had no effect. The reaction was saturable and reversible. Scatchard plots of the data suggested the presence of a single class of high affinity (Kd=0.41 nmol/l) and low capacity (Bmax=26 fmol/mg protein) binding sites. The specificity of the binding reaction was examined using various structural analogs of AVP which displaced 3H-AVP. Arginine-vasotocin proved to be equipotent with AVP, while oxytocin and 1-deamino,8-D-arginine-vasopressin were about 500-fold less effective. Two relatively selective V1-receptor antagonists, dPenTyrMeAVP and d(CH2)5-TyrMeAVP were 2- and 20-fold less potent than AVP, respectively These data strongly suggest that the bovine adrenal medulla contains V1-type receptors for vasopressin, which could be involved in the regulation of the function of chromaffin cells.

Adrenal Medulla↗

PubMed1995

Polymodal dose-response curve for oxytocin in the social recognition test.

Available data concerning the effect of oxytocin on memory are often inconsistent. In the present study it was found that oxytocin, intracerebroventricularly injected to adult male rats in a dose range of 1 fg-10 ng/rat immediately after a 5-minute encounter with a juvenile, significantly reduces the social investigation time of the adult rat towards the same juvenile during a second encounter (120 min later) with two peaks of activity, at 10 fg and 1 ng/rat. Larger doses of oxytocin were ineffective. The oxytocin antagonist d(CH2)5Tyr(Me)-Orn8-vasotocin, injected 5 min before oxytocin by the same route and at the same doses, while being ineffective per se, completely abolished the memory-improving effect of a low dose of oxytocin (1 ng/rat) and, on the other hand, turned into memory-improving the effect of a high dose of oxytocin (500 ng/rat).

Animals↗

PubMed1994

Neonatal stress transiently alters the development of hippocampal oxytocin receptors.

The development of brain oxytocin (OXT) receptors was examined following the mild stress of daily, 20 min separations of infant rats from their mothers (repeated separation condition) or in undisturbed controls. Changes in OXT receptors were characterized in cell membrane preparations, using the OXT receptor ligand [125I]d(CH2)5[Tyr(Me)2Thr4Tyr-NH9(2)]-ornithine vasotocin ([125I]OTA), from rats at 4, 8, 14, 22 postnatal days of age or as adults. In the hippocampus of control animals, [125I]OTA binding was highest at day 4 or 8 and declined thereafter. Repeated separation decreased the Bmax of [125I]OTA binding in whole hippocampus at day 8, an effect that did not persist into adulthood. This effect was found to be confined to the rapidly proliferating, dorsal hippocampus. It has been suggested that brain OXT is involved in both affiliative/social and stress-related behaviors. While the specific function of OXT receptors in hippocampus is currently unknown, mild stress to the infant and the disruption of infant-mother contact transiently alters the normal development of this system.

Animals↗

PubMed1984

Hormonal influence on the duration of short-term and intermediate stages of memory.

In day-old chicks trained on a single trial passive avoidance learning task, ACTH1-24 and corticosterone delayed the formation of long-term memory and the decay of the immediately preceding intermediate memory. This action of ACTH1-24 was attributed to its glucocorticoid activity since ACTH4-10 did not yield the same effect. ACTH1-24 and ACTH4-10, but not corticosterone, enhanced short-term memory retention levels. The effects of arginine vasopressin and arginine vasotocin were similar to those observed with ACTH1-24, but they also delayed the decay of short term memory and hence the formation of intermediate memory. These findings were discussed in the context of hormonal modulation of memory formation and counteraction of antibiotic-induced amnesia.

Adrenocorticotropic Hormone↗

PubMed1988

Hormonal control of sleep-appetitive behaviour and diurnal activity rhythms in the cleaner wrasse Labroides dimidiatus (Labridae, Teleostei).

In its natural environment the cleaner wrasse, Labroides dimidiatus, possesses a hiding place in the reef, where it disappears every night. In my experiments, the Labroides was offered a specific sleeping cave in tanks. Photocells at the entrance to each cave, connected to a printer, counted the sleep-appetitive behaviour (SAB), viz. the investigation of the sleeping-place. Untreated animals visited the cave 45.6 times within 90 min prior to darkness. The swimming activity, which was measured 3 times daily, declined in the course of the light period. During the night the animals are totally motionless. Four substances which are involved in the sleep-influencing processes in mammals were tested. Injection of the neurotransmitter serotonin (0.05-0.5 micrograms/g b.wt. 5-HT) resulted in a decrease of swimming activity and SAB; the 5-HT blocking substance p-chlorophenylalanine (1-8 micrograms/g b.wt. PCPA) intensified this activity and suppressed SAB only in a concentration-range of 10 and 12 micrograms/g b.wt. In addition, the neuromodulatory properties of vasoactive intestinal polypeptide (VIP) and arginine vasotocin (AVT) were investigated. It is noteworthy to mention that VIP (1-1.5 micrograms/g b.wt.) lead to an remarkable increase, and AVT (0.5-4 micrograms/g b.wt.) to a significant reduction of the SAB.

Animals↗

PubMed1986

A comparison of grooming behavior potencies of neurohypophyseal nonapeptides.

We have previously demonstrated that intracerebroventricular (ICV) administration of oxytocin (OXY) enhanced grooming behaviors in male and female rats at a 1 microgram dose. In the present study female rats were injected ICV with 1 microgram OXY or equimolar doses of other peptides. At this dose arginine-vasopressin (AVP), arginine-vasotocin (AVT) and lysine-vasopressin (LVP), as well as alpha-MSH, were as effective as OXY in increasing grooming behavior. At equimolar doses, ACTH1-10, tocinoic acid (the ring structure of OXY) and Pro-Leu-Gly-NH2 (the tail structure of OXY) had no significant effect on grooming behavior. The potency of AVP and AVT was determined across a 0.05-5 microgram dose range. Grooming scores increased in an apparent linear manner across a similar OXY dose range. Both AVP and AVT, however, manifested an inverted U grooming response curve. Maximum grooming scores resulted from a 0.1 microgram dose of AVT or a 0.5 microgram AVP dose. Analyses of the aspects of grooming separately found that nonapeptides OXY, AVP and AVT all elevated body grooming, washing, and scratching. Because AVT and AVP administration resulted in grooming scores significantly higher than OXY at lower doses, we concluded that the CNS is more sensitive to the effects of AVT and AVP on grooming behavior than OXY.

Adrenocorticotropic Hormone↗

PubMed1986

Effects of peripherally injected pituitary peptides on recognition memory in pigeons.

The effects of peripheral injection of arginine vasopressin (AVP), oxytocin (OT), arginine vasotocin (AVT), adrenocorticotrophic hormone (ACTH4-10) and alpha-melanocyte-stimulating hormone (alpha-MSH) were studied, using pigeon subjects and a pair comparison task, with and without intervening delays between stimuli presentation. The highest dose (20 micrograms/kg) of AVT impaired performance by disrupting input, but not storage. General cognitive ability was unimpaired, as were perceptual mechanisms. None of the other peptides affected recognition memory, in that forgetting curves were unchanged when compared with control. The results are discussed in terms of species-specific roles for these peptides.

Adrenocorticotropic Hormone↗

PubMed1987

Endogenous peptides work at multiple sites in the nervous system in the control of gill behaviors in Aplysia.

The suprafusion of two endogenous neuropeptides, arginine vasotocin (AVT) and small cardioactive peptide B (SCPB), over the abdominal ganglion of Aplysia californica significantly affects the ability of a central gill motor neuron to elicit a gill withdrawal response. Gill motor neurons L7 or LDG1 were depolarized to produce the same number of action potentials (APs) on each trial. When AVT (10(-6)M) was suprafused, the motor neurons' ability to elicit a gill movement was suppressed; while SCPB (10(-6)M) superfusion facilitated the response. Neither peptide altered the passive membrane properties of the motor neurons nor did they affect the duration of their APs. These results are consistent with the hypothesis that the peptides act via central control neurons which exert both suppressive and facilitatory control over gill reflex behaviors and associated neural activity.

Animals↗

PubMedDate not supplied

Presence of neurophysins I and II in the human pineal gland: comparison with the content of neurohypophyseal hormones.

We have previously measured the individual content of immunoreactive vasopressin (AVP), oxytocin (OT) and vasotocin (AVT) in 155 human pineal glands, and report here identification and measurement of the neurophysin (Np) content of the same glands, using specific homologous human neurophysin I (HNp I) and neurophysin II (HNp II) radioimmunoassays. Median values for HNp I were for men 47 ng/gland (range, 5 to 1360) and for women 24 ng/gland (range, 5 to 1000); median values for HNp II were respectively 7 ng/gland (range, 2 to 191) and 15 ng/gland (range, 2 to 356) with no significant difference between men and women for HNp I and HNp II but a significant difference (p less than 0.001) between HNp I and HNp II for both sexes. Gel filtration showed that pineal neurophysins were eluted at the same volume as both standard Np and Np from human posthypophyses used as controls. HNp I correlated both with AVP (rs = 0.54 for men and 0.55 for women) and OT (rs = 0.86 for men and 0.57 for women) but not with AVT, while HNp II correlated with AVP (rs = 0.52 for men and 0.53 for women) and OT (rs = 0.92 for men and 0.50 for women) but not with AVT. This study thus confirms the presence of two neurophysins in the human pineal gland and further indicates that they are related to AVP and OT concentrations in the same gland. The results also imply, however, that the presence of immunoreactive AVT (more probably a closely related peptide) is independent of the neurophysins.

Arginine Vasopressin↗

PubMedDate not supplied

Localization of CRF-like immunoreactivity in the brain and pituitary of teleost fish.

Immunocytochemical techniques were applied to brain and pituitary sections of eleven teleost species. A corticotropin-releasing factor (CRF)-antiserum allowed the identification of a CRF-like system in these species. Perikarya were labeled in the preoptic nucleus. Labeled fibers were traced laterally, then ventrally close to the optic chiasma, forming two symmetrical tracts running through the basal hypothalamus. These ended in the rostral neurohypophysis (NH) close to ACTH cells as shown by double immunostaining. Other fibers, often more variquous, ended in the caudal NH close to melanocorticotropic cells. In Salmo fario, small perikarya also stained in the nucleus lateralis tuberis. The CRF-like system appears distinct from that of somatostatin. In Anguilla, adjacent sections stained with CRF- and vasotocin (AVT)-antisera respectively showed that these two peptides coexist in some perikarya. As few fibers containing only AVT end in the rostral NH, they probably do not control ACTH cells directly. AVT fibers terminate mostly in the caudal NH close to melanocorticotropic cells. Some extra-hypothalamic fibers suggest that CRF may also act as a neurotransmitter. The plurality of hormones showing a CRF-like activity in teleosts is considered.

Anguilla↗

PubMedDate not supplied

Hindlimb paralytic effects of arginine vasopressin and related peptides following spinal subarachnoid injection in the rat.

Intrathecal (IT) injection of arginine vasopressin (AVP) in rats caused a transient (less than 30 min), dose-related paralysis of the hindlimbs, loss of hindlimb and tail nociceptive responsiveness, and increased mean arterial pressure. Motor dysfunction was produced with comparable potency by lysine vasopressin (LVP) and arginine vasotocin (AVT); oxytocin (OXY) was approximately 1000 times less potent. Paralysis induced by these peptides was selectively blocked following IT pretreatment with 0.5 nmoles of the vasopressin V1 receptor antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl)tyrosine] Arg8-vasopressin (d(CH2)5[Tyr(Me2)]AVP). Pressor and antinociceptive responses to AVP were also blocked by this compound. However, at higher doses (2-5 nmoles, IT), d(CH2)5[Tyr(Me2)]AVP produced hindlimb paralysis, antinociception, and pressor responses by itself. In contrast to the fiber degeneration, cell loss, and necrosis found in lumbosacral cords of rats persistently paralyzed by other peptides (dynorphin A, somatostatin, and ICI 174864), neuropathological changes were not evident in spinal cords of rats transiently paralyzed by IT AVP. These results indicate that AVP-related peptides affected diverse spinal cord functions through interactions with a V1-like receptor. The similar pattern of cardiovascular and antinociceptive responses to other peptides (dynorphin A, somatostatin, and ICI 174864), which also caused hindlimb paralysis, suggests that the former responses may actually reflect the nonselective consequences of a peptide-induced disruption of spinal cord function, rather than specific shared pharmacological effects.

Animals↗

PubMedDate not supplied

Gi protein mediates adenylate cyclase inhibition by neurohypophyseal hormones in fish gill.

Adenylate cyclase activity was measured on membrane fractions from the gill epithelium of rainbow trout Salmo gairdneri. Basal and glucagon-stimulated activities responded negatively to homologous neurohypophyseal peptides (arginine-vasotocin and isotocin). This inhibitory effect was totally abolished in the presence of pertussis toxin (IAP). The guanine nucleotide dependence of the enzyme was further explored by using GTP, GDP, and their stable analogs Gpp(NH)p, GTP gamma S, and GDP beta S. The results suggest that neurohypophyseal peptides at low concentrations inhibit the adenylate cyclase system directly by way of a Gi-protein, thus implying the intervention of a new type of membrane receptor for these hormones in fish gills.

Adenylate Cyclase Toxin↗