Blockade of the acetylcholine-and histamine-induced changes in the permeability of the blood-brain barrier of normotensive and spontaneously hypertensive rats by atropine and pyrilamine.
We have studied the effects of premedication with either atropine or pyrilamine on the responses of the blood pressure and the permeability of the blood-brain barrier (BBB) in normotensive (WKY) or spontaneously hypertensive (SHR) rats given acetylcholine or histamine. The rats were anesthetized with pentobarbital and the permeability of the BBB evaluated by the extravasation of either 131I-labeled radioiodinated serum albumin (RISA) or 99Tc-labeled sodium pertechnetate (TcO-4). Premedication greatly diminished the hypotensive responses to both acetylcholine and histamine, especially in the SHR animals. Additionally, the premedication blocked the increased permeability of the BBB, especially in SHR rats given TcO-4. The hypotension caused by acetylcholine or histamine in these premedicated animals given RISA again emphasizes the lack of predictability of changes in blood pressure and the permeability of the BBB.
D000109:Acetylcholine / Q000494:pharmacology*; D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects*; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D011738:Pyrilamine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D000631:Aminopyridines; D001285:Atropine; D006632:Histamine; D011738:Pyrilamine; D000109:Acetylcholine