Behavioral effects of thyrotropin releasing hormone

Abstract

Controversial effects of thyrotropin releasing hormone (TRH) on locomotor behavior have been reported. TRH has been reported to increase locomotor behavior when infused into the ventral nucleus accumbens and to have no effect when infused into the dorsal nucleus accumbens. Experiment 1 compared dose dependent changes in locomotor activity in an open field apparatus with TRH infused into these two areas of the brain. Doses infused were 0 (saline), 10 ug, 25 ug and 40 ug TRH. There were no differences found in locomotor behavior between the dorsal and ventral nucleus accumbens. Dose dependent differences were found with rears and wet dog shakes. Animals exhibited more rears and less wet dog shakes when receiving saline. The time course of the behaviors exhibited were also examined. More activity was exhibited in the first 10 min period of the 30 min observation period. Experiment 2 further examined the production of wet dog shakes by TRH. Pretreatment with parachloroamphetamine decreased wet dog shakes, as well as locomotor activity. These results suggested that the neurotransmitter serotonin may slo be involved with the effects of TRH on locomotor behavior.