To investigate the involvement of dopamine (DA) in nociceptive sensitivity-behavioral reactivity regulation in animals during aversive states of different nature, the influence of pharmacologically-induced decrease and increase of DA neurotransmission on vocalization and movement reactivity were studied in rats in free behavior, during restraint stress, after acute trauma of an extremity and under intraperitoneal acetic acid administration. The influence of longterm increase (apomorphine in a high dose) and decrease (haloperidol, apomorphine in a low dose) on suprarenals weight and gastric ulceration in animals exposed by polymodal aversive stimulation was also studied. The data obtained are discussed in relation with; 1. DA involvement in regulation of nociceptive sensitivity and behavioral reactivity in aversive environment; 2. the role of DA and endogenous opioid peptides in endogenous analgesic mechanisms; 3. the functional significance of cerebral DA in organization and realization of various types of an organism's adaptive activity produced by different environmental and homeostatic variables; and 4. the interaction of DA and endogenous opioid peptides in mediation of this activity.