Some Cardiorespiratory Effects of Histamine, 5-Hydroxytryptamine, and Compound 48/80 in the Calf

Abstract

LEWIS, A. J., and EYRE, P. 1972. Some cnrciiorespiratory eficts of histamine, 5-hydror~ytryptamine, and compoalnd 48/80 in the calf. Can. 9. Playsiol. Phal.maco1. 58, 545-553. Tine cardiorespiratory responses to histamine, -hydroxytryptamine, and cornpourad 48/80 have been examined in the calf. The simultaneous rmeasurement of whole blood histamine and plasma 5-hydroxytryptamine during cc~rraporand 48/80 infusion showed significantly elevated levels that followed a biphaslc pattern. However, mast cell changes i n the sites examined were minimal and there was no significant difference in histarnine concentrations in tissues examined. Marked systemic effects were observed and included an initial rise in femoral arterial blood pressure which was Iater followed by a terminal hypstension and death. Pulmonary arterial blood pressure ant1 venous pressure were both elevated and dyspnoeic respiration was also evident. A combination of ~mepyramine and tnethysergide inhibited the toxicity of compound 48/80 which suggested that histamine and 5-laydroxytryptamine played a major role in the toxic response tes this substance in the calf.