Previous studies indicate that a variety of pharmacological agents interfere with the prepulse inhibition of the acoustic startle (PPI) response including phencyclidine (PCP), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), amphetamine, and apomorphine. Strain differences have been observed in the ability of apomorphine to disrupt PPI, although the degree to which these strain differences...
Analgesia induced by footshock (2 mA, 30 s) is decreased by the 5-HT releaser, fenfluramine, and the rapidly acting 5-HT agonist, 5-methoxy-N,N-dimethyltryptamine (5-MeODMT). These decreases are blocked by the 5-HT antagonists, cyproheptadine and methiothepin. However, the antagonists when given alone do not influence shock-induced analgesia. Therefore, analgesia induced by brief footshock in...