Angiotensin II inhibits the release of [3H]acetylcholine from rat entorhinal cortex in vitro.
The effects of angiotensin I and II on basal potassium-induced release of [3H]acetylcholine were investigated in slices of rat entorhinal cortex. Potassium (10-25 mM) produced a concentration-dependent increase in the release of [3H]acetylcholine in the presence of extracellular calcium. Angiotensin II (10(-9)-10(-5) M) (but not angiotensin I) reduced the potassium-induced release of [3H]acetylcholine in a concentration-related manner to 60% of control levels, but did not effect basal tritium release. The effect of angiotensin II was antagonised by [1-sarcosine, 8-threonine] angiotensin II, an angiotensin II receptor antagonist, but not by agents acting on alpha- and beta-adrenoceptors, muscarinic, nicotinic, histamine or 5-hydroxytryptamine receptors nor by the angiotensin converting enzyme (ACE) inhibitor SQ 29852. The results indicate that angiotensin II acting via an angiotensin II receptor can inhibit the release of [3H]acetylcholine in slices of the rat entorhinal cortex. It is hypothesised that the ability of ACE inhibitors to facilitate cognitive processes may be related to a reduced availability of angiotensin II.
Barnes
J M
JM
Postgraduate School of Studies in Pharmacology, University of Bradford, U.K.
Barnes
N M
NM
Costall
B
B
Horovitz
Z P
ZP
Naylor
R J
RJ
D000109:Acetylcholine / Q000493:pharmacokinetics*; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D000804:Angiotensin II; C014805:angiotensin II, Sar(1)-Thr(8)-; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium