Histamine H1 receptor activation mediates the preferential release of adrenaline in the rat adrenal gland.
Histamine elicited the release of catecholamines from "in vitro" perfused rat adrenals with an EC50 of 3 microM. This concentration was in the same range as those which caused a fall in the arterial blood pressure when infused intravenously in anaesthetized rats. Histamine stimulation was potently blocked by dexclorfeniramine (IC50 = 300 pM), but unaffected by ranitidine, suggesting the involvement of H1 receptors. Histamine release preferentially adrenaline. Mast cells were not detected within adrenal medulla by histochemical techniques. Compound 48/80 did not trigger catecholamine release. Catecholamine secretion evoked by splanchnic nerves stimulation was not modified by a combination of H1 and H2 antagonists. In conclusion, the histamine that elicited adrenaline release from rat adrenals comes from blood circulation not from local mast cells or splanchnic nerves. These effects are mediated through the activation of H1 receptors.
Borges
R
R
Unidad de Farmacología, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain.
D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002744:Chlorpheniramine / Q000494:pharmacology; D004837:Epinephrine / Q000378:metabolism*; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006636:Histamine Release / Q000187:drug effects / Q000502:physiology; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D011899:Ranitidine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011969:Receptors, Histamine H1 / Q000187:drug effects* / Q000502:physiology*; D013153:Splanchnic Nerves / Q000378:metabolism
D011969:Receptors, Histamine H1; C018904:dexchlorpheniramine; D002744:Chlorpheniramine; D006632:Histamine; D011899:Ranitidine; D009638:Norepinephrine; D004837:Epinephrine