Effect of thyrotropin releasing hormon injected into lateral ventricle on respiration and blood pressure in rabbits

Abstract

Experiments were carried out on 48 unanesthetized, vogotomized, gallamine triethiodide immobilized and artificially ventilated rabbits. Injection of thyrotropin releasing hormone (TRH) into lateral ventricle resulted in a marked increase in respiratory rate and phrenic nerve discharge frequency and a significant elevation of arterial blood pressure. However, no change in respiratory activity and blood pressure was observed when an equal dose of TRH was injected intravenously. On the contrary, morphine administered intravenously produced a decrease in respiratory activity and blood pressure, which could be reversed by TRH applied intralateral-ventricularly. These findings indicate that TRH can stimulate respiratory activity, elevate blood pressure centrally and antagonize morphine-induced depression in respiration and blood pressure.

Keywords

thyrotropin releasing hormone morphine / intralateral-ventricular injection / phrenic nerve discharge / arterial blood pressure

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