Effects of right atrial distension on the activity of magnocellular neurons in the supraoptic nucleus

Regina R. Grindstaff, Ryan J. Grindstaff, J. Thomas Cunningham

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

A small balloon placed at the junction of the superior vena cava and right atrium was used to stimulate cardiac volume receptors in pentobarbital sodium-anesthetized male rats. Extracellular recordings were obtained from antidromically identified vasopressinergic and oxytocinergic neurosecretory cells of the supraoptic nucleus. Cells were considered sensitive to the stimulus if balloon inflation resulted in a 30% change in firing frequency. Balloon inflation that did not stretch the caval-atrial junction had no significant effect on vasopressin neurons (n = 51, P > 0.05). Stretch of the caval-atrial junction decreased the firing activity in 64 of 83 putative vasopressin neurons (P < 0.01 compared with control). Stretch of the caval- atrial junction influenced the firing activity of only 3 of 26 antidromically activated oxytocinergic neurons, an effect not statistically different from control (P > 0.05). When bilateral vagotomy was performed while recording from vasopressin neurons (n = 5), sensitivity to stretch of the caval-atrial junction was eliminated. Cardiac receptors located at the junction of the superior vena cava and right atrium may be important in regulating the activity of vasopressinergic but not oxytocinergic neurons of the supraoptic nucleus.

Original languageEnglish
Pages (from-to)R1605-R1615
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume278
Issue number6 47-6
DOIs
StatePublished - Jun 2000

Keywords

  • Cardiac receptor
  • Oxytocin
  • Vasopressin

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