Beta-endorphin: a common factor in the antihypertensive action of clonidine-type imidazolines in spontaneously hypertensive rats.
The hypotensive action of two novel imidazolinic alpha-adrenergic agonists (ICI-106270 and UK-14304) with similar pharmacological properties to clonidine was shown in spontaneously hypertensive (SH) rats. The antihypertensive effect of the clonidine-type agents was prevented by either peripheral administration of the opiate antagonist naloxone or by intracerebroventricular (i.c.v.) injection with a specific antibody against human beta-endorphin (BEN). A dose-response relationship was found for the hypotensive effect of i.c.v. given BEN in SH rats, the low blood pressure being significantly reversed by further treatment with either naloxone or anti-beta h-endorphin. These data confirm and extend the notion of a BEN mediation in the antihypertensive action of clonidine-type alpha-adrenergic agonists in SH rats.
Naranjo
J R
JR
Fernandez-Roman
M
M
Urdin
M C
MC
Fuentes
J A
JA
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D000068438:Brimonidine Tartrate; D003000:Clonidine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000502:physiology*; D006973:Hypertension / Q000503:physiopathology*; D007093:Imidazoles / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D001615:beta-Endorphin
D000959:Antihypertensive Agents; D004723:Endorphins; D007093:Imidazoles; D011810:Quinoxalines; D000068438:Brimonidine Tartrate; D001615:beta-Endorphin; C032860:ICI 106270; D003000:Clonidine