Acute central effects of L-glutamate in pentobarbital-anesthetized dogs.
Microinjections of L-glutamate (10(-10) to 2 X 10(-8) mol/kg) into the nucleus of tractus solitarii produced a dose-dependent increase in mean arterial pressure and a decrease in heart rate. L-Glutamate-induced hypertension was prevented by spinal transection and pretreatment with atropine (1 mg/kg iv) reversed the bradycardia. L-Glutamate also produced a dose-dependent increase in mean arterial pressure when injected intravenously and into the cisterna magna, but the dose-effect curves were shifted to the right. Finally, pretreatment with hexamethonium (30 mg/kg iv) abolished the hypertension resulting from intravenous injections of L-glutamate. These data demonstrate that the nucleus of tractus solitarii may play a determinant role in the central pressor effects of L-glutamate. In addition, we demonstrated that this hypertension was due to a central sympathetic stimulation and that the autonomic nervous system also mediated the pressor effects of intravenous L-glutamate.
D000758:Anesthesia; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005971:Glutamates / Q000008:administration & dosage / Q000494:pharmacology*; D018698:Glutamic Acid; D006339:Heart Rate / Q000187:drug effects; D006584:Hexamethonium Compounds / Q000494:pharmacology; D006973:Hypertension / Q000139:chemically induced; D007276:Injections, Intraventricular; D008297:Male; D008751:Methylene Blue; D010424:Pentobarbital; D011433:Propranolol / Q000494:pharmacology
D005971:Glutamates; D006584:Hexamethonium Compounds; D018698:Glutamic Acid; D001285:Atropine; D011433:Propranolol; D010424:Pentobarbital; D008751:Methylene Blue