Reactivity of isolated human cerebral arteries to biogenic amines.
Serotonin (5-HT), histamine, norepinephrine, methoxamine and isoproterenol caused dose-dependent contraction of human cerebral arteries. The potency of 5-HT was greater among test agents in the basilar arteries, whereas it was equivalent to that of norepinephrine in human anterior, middle and posterior cerebral arteries. Acetylcholine and carbachol (10(-9)-10(-5) M) caused a negligible response in human cerebral arteries. Contractile response to 5-HT was greater in the distal rather than middle portion of the human basilar arteries while this order was reversed in the response to norepinephrine. Tyramine (10(-4) M) caused tonic contraction and nicotine (10(-4) M) and electrical transmural stimulation produced phasic contraction of arteries which were antagonized by adrenergic blocking agents. Adenine nucleotides failed to cause relaxation and only high concentration of adenosine caused a minute relaxation. However, papaverine and nitroglycerin caused marked relaxation. These results suggest that adrenergic mechanism may play a role in the regulation of vascular tone in human cerebral arteries.
D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000368:Aged; D001679:Biogenic Amines / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects*; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology; D005996:Nitroglycerin / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D009711:Nucleotides / Q000494:pharmacology; D010208:Papaverine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
D001679:Biogenic Amines; D009711:Nucleotides; D012701:Serotonin; D009538:Nicotine; D006632:Histamine; D002217:Carbachol; D010208:Papaverine; D005996:Nitroglycerin; D008729:Methoxamine; D000241:Adenosine; D007545:Isoproterenol; D000109:Acetylcholine; D009638:Norepinephrine; D014439:Tyramine