Vasopressin reduces release from vasopressin-neurons and oxytocin-neurons by acting on V2-like receptors

The neurohypophyseal neuropeptides (Arg8)-vasopressin (AVP) and [pGlu4, (where pGlu is pyroglutamic acid and Cyt is cystine) facilitate the retention of one-trial-learning passive avoidance behavior in rats when administered into the cerebral ventricle immediately after the learning trial. The fragment [pGlu4,Cyt'JAVP-(4-8) was considerably more effective than AVP. Oxytocin (OXT) and [pGlu", have the opposite effect and attenuate passive avoidance behavior also when administered into the cerebral ventricle after the learning trial. Again the fragment was more active than the parent molecule. The ancient arginine-containing neurohypophyseal hormone vasotocin in "high" doses (10 ng) had a vasopressin-like effect and in "low"

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“…Accordingly, V2-type vasopressinergic receptors have been suggested to be present in the brain (14). More Table 1.…”

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confidence: 99%

Interactive effects of neurohypophyseal neuropeptides with receptor antagonists on passive avoidance behavior: mediation by a cerebral neurohypophyseal hormone receptor?

Wied

Elands

Kovaćs

1991

Proc. Natl. Acad. Sci. U.S.A.

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“…In an earlier study we showed that peripherally administered vasopressin (1 nmol, i.p.) exerts a negative feedback influence on both vasopressin neurones and oxytocin neurones during acute osmotic stimulation (Cheng and North 1989).…”

Section: Discussionmentioning

confidence: 99%

“…had elapsed from the initial sampling, the rat was injected intraperitoneally with I m mL of 0.9% saline. Intraperitoneal administration was used instead of an intravenous route so that the possible feedback influence of OT on release from magnocellular neurones could be studied under the same conditions employed earlier to examine the feedback effects of VP on such neurones (Cheng and North 1989). Blood pressure was recorded 10 min later and the animal was returned to its home cage.…”

Section: Surgical Preparationmentioning

confidence: 99%

“…This apparent negative feedback effect of vasopressin on its own release appeared to be exercised entirely through V2-like receptors, while its effect on oxytoein release seemed to largely, though not entirely, involve the same mechanism (Cheng and North 1989). The peripheral route of administration suggests that the receptors involved are located outside the central nervous system.…”

Section: Introductionmentioning

confidence: 97%

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Absence of negative feedback by oxytocin on release from magnocellular neurones in conscious rats

Cheng¹,

North²

1992

Can. J. Physiol. Pharmacol.

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Peripheral administration of vasopressin (VP) was previously shown to exert a negative feedback influence on its own release and on the release of oxytocin (OT). In this study we examined the possible influence that OT has on the function of hypothalamic magnocellular neurones. Oxytocin was administered intraperitoneally and its effects on release from VP neurones and from OT neurones were determined as indexed by plasma concentrations of vasopressin-associated neurophysin ([VP-RNP]) and oxytocin-associated neurophysin ([OT-RNP]) under basal conditions and conditions of high plasma osmolality (Posm) induced by acute salt loading. Studies were performed on conscious, chronically instrumented Long-Evans rats. Oxytocin (1 nmol or 10 nmol) dissolved in 1 mL of 0.9% saline was administered intraperitoneally to animals 1 h before they received an intravenous infusion of hypertonic saline over 60 min at a rate designed to raise Posm by approximately 0.75 mosmol.min-1. Intraperitoneal injection of vehicle or 1 nmol of OT did not significantly alter [VP-RNP], [OT-RNP], or basal Posm. Administration of 10 nmol OT also had no effect on [VP-RNP] or [OT-RNP], but this dose of peptide significantly lowered basal Posm (299 +/- 2 to 290 +/- 2 mosmol/kg H2O, p less than 0.001). Both doses of OT did not significantly alter the responsiveness of VP neurones to hyperosmotic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Peripheral administration of dDAVP (48), a V,-AVP receptor agonist, does not directly interfere with the secretory activity of VP-producing neurons but by retaining body water, reduces VP release (49). The reduced release of VP induced a significant decrease in uptake of MAb by PVN neurons.…”

Section: Quantitative Analysis Of Vp-mab Uptake 359mentioning

confidence: 99%

Neuronal Uptake of Monoclonal Anti‐Vasopressin Antibodies in vivo and Relationship with the Physiological Status of Vasopressin Neurosecretory Cells

Burlet¹,

Arahmani²,

Tankosic³

et al. 1990

J Neuroendocrinology

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Key words: vaso p less I n , i rn rn u n oc y t oc he m is t ry , n e u ro n a I uptake , in vivo, rno rp h o me t r ic analysis. AbstractMouse monoclonal anti-vasopressin antibody was injected just above one hypothalamic paraventricular nucleus of the rat brain. lmmunocytochemistry and morphometric analysis showed that the antibody was taken up by neurons with the size and stereotaxic distribution of vasopressin-producing neurons. Labelled neurons were counted with an electronic image analyser. When the rats were deprived of drinking water for 48 h before injection, specific uptake was significantly increased in the caudal part of the nucleus. Conversely, rehydration following dehydration or chronic treatment with 1-deamino-8-D-arginine vasopressin significantly decreased neuronal uptake, mainly in the rostra1 subdivision of the nucleus. By contrast, bilateral adrenalectomy performed 2 weeks before injection did not modify the number of labelled magnocellular neurons, though the accumulation of injected antibody in the external layer of t h e median eminence indirectly demonstrated the stimulation of antibody uptake by parvocellular vasopressin neurons.The number of labelled neurons w a s therefore directly related to the physiological state of the vasopressin-producing neurons. Further investigations will have to be performed to prove that the immunological targeting of peptidergic neurons offers a new tool to act in vivo on central neurons.It has recently been demonstrated in our laboratory that monoclonal antibodies (MAbs) raised against a neuropeptide, vasopressin (VP), penetrated into neurons when they were injected into the brain (I). This uptake was specific and occurred in vivo in VPproducing neurons. Labelled neurons were revealed in the brain of rats sacrificed 5 min to 3 h after the injection. VP-MAbs were then transported to neuron terminals, and this transport was inhibited by the prior injection of colchicine. Despite the high concentration of injected specific immunoglobulins and a diffusion volume including all VP neurons of the injected area most, though not all of the VP neurons, were labelled in vivo. This finding suggested that uptake of VP-MAb was modulated and it prompted the question whether neuronal activity might be responsible for this modulation. The present study was designed to obtain further information about the number of VP-producing neurons which take up VP-MAbs in the normal rat. In addition, quantitative analysis of labelled neurons was performed in rats deprived of drinking water ('dehydrated' rats), in rats given water after a period of deprivation ('rehydrated' rats), in rats chronically infused with 1 -deamino-8-D-arginine-VP (dDAVP), or in rats subjected to bilateral adrenalectomy. All these experimental situations are known to have an impact on VP synthesis in different ways: the magnocellular VP neurons of the supraoptic (SON) and paraventricular (PVN) nuclei are mainly involved in the modifications of hydric balance (2) whereas adrenalectomy stimulates a subset of parv...

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Vasopressin reduces release from vasopressin-neurons and oxytocin-neurons by acting on V2-like receptors

Cited by 36 publications

References 15 publications

Interactive effects of neurohypophyseal neuropeptides with receptor antagonists on passive avoidance behavior: mediation by a cerebral neurohypophyseal hormone receptor?

Interactive effects of neurohypophyseal neuropeptides with receptor antagonists on passive avoidance behavior: mediation by a cerebral neurohypophyseal hormone receptor?

Absence of negative feedback by oxytocin on release from magnocellular neurones in conscious rats

Neuronal Uptake of Monoclonal Anti‐Vasopressin Antibodies in vivo and Relationship with the Physiological Status of Vasopressin Neurosecretory Cells

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