Presence of functional vasopressin V1 receptors in rat vagal afferent neurones

X. Gao, P. A. Phillips, R. E. Widdop, D. Trinder, B. Jarrott, C. I. Johnston

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The nucleus of the solitary tract (NTS) is one of the brain regions by which arginine vasopressin (AVP) influences blood pressure. This series of experiments in adult male rats was designed to determine whether the AVP binding sites which have been demonstrated in the NTS by in vitro autoradiography might be presynaptic on vagal afferents from the nodose ganglion; whether the AVP binding sites on vagal afferent neurones are functional receptors; and whether vagal transport of AVP receptors to other organs also occurs. High affinity binding sites (using the selective V1 antagonist radioligand [125I][d(CH2)5,Sar7]AVP and in vitro autoradiography) with characteristics of V1 receptors in the medial sub were reduced by 40% ipsilateral to nodose ganglionectomy. The nodose ganglion itself also contained high affinity V1 AVP binding sites that localis over cell bodies of vagal sensory neurones. That these binding sites were functional receptors was apparent when low concentrations of AVP but not oxytocin were found to depolarise the isolated nodose ganglion utilizing the 'silicone grease gap' technique. Furthermore, the actions of AVP were antagonised by low concentrations of a selective V1 receptor antagonist. However, there was no accumulation of AVP binding sites adjacent to either the proximal or distal vagal ligations suggesting that peripheral vagal transport of AVP receptors may not occur. Therefore these results are consisten with functional AVP V1 receptors occurring in the nodose ganglion. These receptors may occur on central terminals of vagal sensory neurones in the medial subnucleus of the NTS, but there was no evidence for peripheral transport of AVP V1 receptors.

Original languageEnglish
Pages (from-to)79-82
Number of pages4
JournalNeuroscience letters
Volume145
Issue number1
DOIs
Publication statusPublished - 28 Sep 1992
Externally publishedYes

Keywords

  • Arginine vasopressin
  • Brain
  • Nodose ganglion
  • Nucleus tractus solitarii
  • Receptor
  • Vagus

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