Caudal ventrolateral medulla. A region responsible for the mediation of vasopressin-induced pressor responses.
We localized glutamate-sensitive sites in the ventrolateral medulla of the rat with the spinal cord cut at C. When unilaterally injected into a circumscribed region of the caudal ventrolateral medulla, L-glutamate (30-300 ng) elicited a dose-dependent increase in arterial pressure. The pressor response was accounted for by an increased release of vasopressin because it was abolished by the intravenous injection of a vasopressin antagonist. Bilateral microinjections of kainic acid (50 ng) into the ventrolateral glutamate-sensitive area markedly reduced a vasopressin-induced pressor response to kainic acid (30 ng), injected bilaterally into the nucleus tractus solitarii. It is concluded that the glutamate-sensitive neurons in the caudal ventrolateral medulla are involved in mediation of the vasopressin-induced pressor response arising from the nucleus tractus solitarii.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002818:Cordotomy; D005971:Glutamates / Q000494:pharmacology; D007608:Kainic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D009474:Neurons / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000378:metabolism*
D005971:Glutamates; D014667:Vasopressins; D007608:Kainic Acid