Thyrotropin-releasing hormone: physiological concomitants of behavioral excitation

Two doses (10 microng and 100 microng) of thyrotropin-releasing hormone (TRH) or saline were injected intraventricularly in rabbits pretreated with either saline, pentobarbital or phenobarbital. Behavior, EEG patterns, respiration rate and heart rate were monitored for 100 min posttreatment. TRH significantly altered all physiological indices except heart rate in both barbiturate- and saline-pretreated animals. The results support the contention that TRH modified central functioning by direct action. Results are discussed in terms of barbiturate antagonism and excitatory effects of TRH.