Behavioral Effects of Vasopressin

Abstract

In the mid-1960s it was reported that removal of the neurointermediate lobe of the pituitary results in a disturbance of shuttle-box avoidance behavior of rats (De Wied 1965). Subsequent studies revealed that treatment with vasopressin normalizes the disturbed behavior of posterior lobectomized rats, and it was also shown that the disturbed behavior is unrelated to the disturbance in water metabolism (De Wied 1969). Later it appeared that pitressin or vasopressin given during either the acquisition or the extinction period of shuttle-box avoidance behavior induces a long-lasting resistance to extinction of the learned avoidance response in intact rats (De Wied and Bohus 1966; De Wied et al. 1974) Similar effects were obtained in a one-way active avoidance paradigm (De Wied 1971; Schulz et al. 1974; Koob et al. 1981, 1986). A single injection of vasopressin induced a long-term, dose-dependent inhibition of extinction of the conditioned avoidance response. This effect was still present after the administered peptide had disappeared from the body, which suggests that vasopressin triggers a long-term effect on the maintenance of a learned response (De Wied 1971; De Wied et al. 1974, 1976; Van Wimersma Greidanus et al. 1973; Stark et al. 1978). Similar or comparable effects have been reported by other researchers (Schulz et al. 1974; Koob et al. 1981; Le Moal et al. 1981), but still others have failed in this respect (see for review Saghal 1984). The critical time period for this behavior effect of vasopressin to occur lasted some hours. Vasopressin was fully active when administered in association with behavior that occurred 1 h prior to or after injection (King and De Wied 1974). Administration 3 h before or after the behavioral session markedly decreased the effectiveness of the treatment, while administration at a time interval of 6 h was ineffective (De Wied 1971, 1973; Bohus et al. 1972).