Captopril potentiates the vasodepressor action of Met-enkephalin in the anaesthetized rat.
The transient vasodepressor action of Met-enkephalin (10-80 micrograms kg-1, i.v.) in anaesthetized rats was significantly potentiated by the angiotensin-converting enzyme inhibitor, captopril (2 mg kg-1, i.v.); at this dose, it failed to modify the transient vasodepressor action of the non-specific vasodilator, nitroprusside (2.5, 5.0, 10 micrograms kg-1, i.v.). Captopril (2 mg kg-1, i.v.) caused a slow, progressive fall in the blood pressure of anaesthetized spontaneously hypertensive (SH) rats when compared to vehicle-treated controls. Pretreatment with naloxone (1.5 mg kg-1, i.v.) 30 min earlier failed to alter significantly the hypotensive action of captopril in anaesthetized SH rats. It was concluded that although captopril potentiated the vasodepressor action of Met-enkephalin in anaesthetized normotensive rats, potentiation of endogenous opioids does not appear to be involved in the hypotensive action of captopril in anaesthetized SH rats.
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002216:Captopril / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D008297:Male; D011392:Proline / Q000031:analogs & derivatives*; D051381:Rats; D011919:Rats, Inbred Strains
D004744:Enkephalin, Methionine; D011392:Proline; D002216:Captopril