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SOME CARDIOVASCULAR EFFECTS OF MONOAMINE OXIDASE INHIBITORS IN UNANAESTHETIZED RATS
Author(s) -
Marwood John F.,
Huston Vicki,
Wall Kim T.
Publication year - 1985
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1985.tb02319.x
Subject(s) - tranylcypromine , tyramine , pargyline , harmaline , monoamine oxidase , serotonin , chemistry , blood pressure , endocrinology , medicine , pharmacology , enzyme , biochemistry , receptor
SUMMARY 1. The effects of four monoamine oxidase (MAO) inhibitors on the blood pressure of conscious normotensive and DOC‐salt hypertensive rats were measured. Harmaline (20 mg/kg p.o.), pargyline (100 mg/kg p.o.) and tranylcypromine (10 mg/kg p.o.) all lowered blood pressure significantly in both normotensive and hypertensive rats whereas methylaplysinopsin (10 mg/kg p.o.) had no effect on blood pressure. 2. The effects of these MAO inhibitors on blood pressure responses to serotonin, tyramine and β‐phenylethylamine were determined in conscious normotensive rats. Pargyline and tranylcypromine shifted the dose‐response curves for tyramine and β‐phenylethylamine, but not serotonin, to the left, indicating inhibition of type B MAO. Harmaline and methylaplysinopsin shifted the dose‐response curves for tyramine and serotonin but not β‐phenylethylamine, to the left, indicating inhibition of type A MAO. 3. Since the four antagonists tested inhibited at least one form of MAO, and yet not all of these MAO inhibitors lowered blood pressure, we suggest that our results are consistent with the view that the hypotensive action of MAO inhibitors is not necessarily related to inhibition of MAO.