Vasopressin-secreting neurones of the paraventricular nucleus respond to oropharyngeal application of hypertonic saline.
Responses of electrophysiologically identified vasopressin (VP)-secreting neurones of the hypothalamic paraventricular nucleus in the rat were recorded following the application of hypertonic saline (2-4 M) to the tongue and oropharynx. Fourteen of the 15 VP-secreting neurones were excited by the stimulus, response onset occurring within a few seconds. Of the 5 neighbouring unidentified neurones, or those identified as projecting to the median eminence, 3 were also found to respond to the stimulus. All of the responses were sustained during the period of application and were reversed following wash-off with distilled water, when neurones were found to be substantially inhibited. The results of this study indicate a role of ascending gustatory sensory afferent innervation as a predictive indicator of changing plasma osmotic pressure.
Saphier
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Department of Neurology, Hadassah University Hospital, Israel.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D008297:Male; D009960:Oropharynx / Q000294:innervation*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D014059:Tongue / Q000294:innervation; D014667:Vasopressins / Q000378:metabolism*
D012462:Saline Solution, Hypertonic; D014667:Vasopressins