The effect of intracerebroventricular 3-mercaptopropionic acid on blood pressure and heart rate in the rat.
Intracerebroventricular (i.c.v.) injection of 3-mercaptopropionic acid (3-MP, 250 micrograms/10 microliter) elicited an elevation of blood pressure in a dose-dependent manner in anaesthetized rats. This elevation of blood pressure could be blocked by treatment with amino-oxyacetic acid (AOAA, 25 mg/kg, i.p.) 5 h prior to the i.c.v. injection of 3-MP. Given intraperitoneally (i.p.), 3-MP (75 mg/kg) had no effect on blood pressure or heart rate. I.c.v. injection of 3-MP produced a selective decrease in GABA content in the diencephalon and mesencephalon, whereas i.p. injection of 3-MP caused a decrease in GABA content in all regions of brain, including telencephalon, diencephalon, mesencephalon, pons and medulla. The results suggest that the elevation of blood pressure induced by i.c.v. injection of 3-MP may be the result of a selective depletion of GABA in diencephalon and/or mesencephalon. Decreases in GABA content in brain regions other than diencephalon and mesencephalon may lead to an opposite effect in modulating blood pressure.
D015097:3-Mercaptopropionic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors; D000625:Aminooxyacetic Acid / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007276:Injections, Intraventricular; D051381:Rats; D013438:Sulfhydryl Compounds; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D013438:Sulfhydryl Compounds; D000625:Aminooxyacetic Acid; D005680:gamma-Aminobutyric Acid; D015097:3-Mercaptopropionic Acid; D000612:4-Aminobutyrate Transaminase