Direct and neuromodulatory effects of histamine on isolated goat cerebral arteries.
1. The effects of histamine on isolated goat middle cerebral artery were examined using two experimental approaches: recording of isometric tension and measurement of [3H]-noradrenaline efflux. 2. Cumulative addition of histamine (10(-7)-3 x 10(-2)M) and 2-pyridylethylamine (2-PEA, 10(-6)-3 x 10(-2)M) produced concentration-dependent contractile responses. Preincubation with diphenhydramine (10(-7), 10(-6)M) or cimetidine (10(-7), 10(-6)M) competitively inhibited the histamine-induced contractile response. 3. Endothelium denudation enhanced the contractile effects of histamine. 4. Transmural electrical stimulation elicited contractions which were enhanced by histamine (10(-7)M), 2-PEA (10(-6)M) and dimaprit (10(-4)M). Diphenhydramine (10(-5)M) inhibited the action of histamine, but cimetidine did not. 5. Noradrenaline (10(-8)-10(-4)M) elicited concentration-dependent contractions which were unaffected by histamine (10(-7)M). 6. In arteries preloaded with [3H]-noradrenaline, transmural electrical stimulation induced an increase in the tritium efflux, which was enhanced in the presence of histamine (10(-7)M). 7. Therefore, histamine contracts cerebral arteries via specific non-endothelial H1-receptors, and enhances perivascular adrenergic neurotransmission through specific presynaptic H1-receptors by a mechanism involving increases in noradrenaline release.
Miranda
F J
FJ
Centro de Investigación, Hospital La Fe, Valencia, Spain.
Torregrosa
G
G
Salom
J B
JB
Alabadí
J A
JA
Alvarez
C
C
Alborch
E
E
D000818:Animals; D002536:Cerebral Arteries / Q000187:drug effects* / Q000294:innervation; D004558:Electric Stimulation; D005260:Female; D006041:Goats; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism; D011969:Receptors, Histamine H1 / Q000187:drug effects
D011969:Receptors, Histamine H1; D006632:Histamine; D009638:Norepinephrine