Effect of thyrotropin releasing hormone on heart rate and visual evoked potentials in rats.

The effect of injection of 0.3 microgram of thyrotropin releasing hormone (TRH) into the third ventricle on heart rate and photically evoked potentials in the midbrain reticular formation in urethane-anesthetized rats was studied. TRH increased the heart rate and amplitude of the visual evoked potentials within a few minutes following injection. The intraventricular injections of LHRH, consituent amino acids of TRH and intraperitoneal TSH did not exert any effect. This indicates that TRH is effective in the central nerveous system in inducing tachycardia in the rat.