It is well known that histamine produces constriction via H1 receptors and decreases tracheal smooth muscle tone via H2 and H3 receptors. In addition, it has already been reported that 3-methylhistamine and phenylethylamine are competitive antagonists of histamine N-methyl-transferase (HMT), the enzyme responsible for rapid inactivation of histamine. Our results suggest the possibility that 3me...

Histamine is present in high concentrations in the intestine and we investigated the possibility that it might have a role here in intestinal transport. When added to the basal side of rabbit ileal mucosa in vitro histamine (10(-4)M) induced a short-lived increase in electrical potential difference and short circuit current. It inhibited net chloride absorption but did not influence sodium tran...

WOODS, JAMES R., JR., C. R. BRINKMAN, III, A. DANDAVINO, K. MURAYAMA, AND N. S. ASSALI. Action of histamine and H, and H, blockers on the cardiopulmonary circulation. Am. J. Physiol. 232(l): H73-H78, 1977 or Am. J. Physiol.: Heart Circ. Physiol. l(1): H73-H78, 1977. -Systemic and pulmonary hemodynamic responses to histamine were investigated in chronically instrumented unanesthetized nonpregnan...

Receptors for small endogenous hormones on human leukocytes were studied by insolubilizing the hormones and incubating them with the cells. Histamine, norepinephrine, and prostaglandin E(2) (PGE(2)) were conjugated to either of two types of carrier: (bovine or rabbit) serum albumin or a random copolymer of DL-alanine and L-tyrosine. The conjugates were linked to agarose beads (Sepharose) and th...

Hemodynamic responses to histamine were investigated in the anesthetized rabbit. Intravenous injections of histamine induced dose-dependent decreases in systemic arterial pressure that were blocked by the H1-receptor antagonist pyrilamine but not the H2 antagonist cimetidine. Injections of histamine and the H1 agonist 6-[2-(4-imidazolyl)ethylamine]- N-(4-trifuormethylphenyl)-heptanecardoxamide ...