Monamines as mediators of avoidance-escape behavior.
A series of three experiments were carried out to test the hypothesis ("motor activation deficit" hypothesis) that the avoidance-escape deficits observed following certain highly stressful conditions result from changes in activity of noradrenergic (or other monominergic) neural systems. These studies indicate that: (1) Depletion of monamines by a single injection of tetrabenazine produces an active avoidance-escape deficit when the avoidance-escape response involves a relatively high degree of motor activity but not when a minimum of motor activity is required. This parallels results found when animals are acutely exposed to a stressor prior to avoidance-escape testing. (2) Daily injections of tetrabenazine for a period of two weeks, like daily exposure to inescapable shock for the same period of time, markedly attenuates the magnitude of the avoidance-escape deficit produced by either a single injection of tetrabenazine or single session of inescapable shock. (3) Decreasing the stress-induced depletion of monamines by the use of an MAO inhibitor serves to protect the animals from the effects of inescapable shock, markedly reducing the avoidance-escape deficit produced by such shock. It is concluded that these results are consistent with the motor activation deficit hypothesis.
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D004597:Electroshock; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000502:physiology*; D010293:Pargyline / Q000494:pharmacology; D051381:Rats; D013315:Stress, Psychological / Q000502:physiology; D013747:Tetrabenazine / Q000494:pharmacology; D013997:Time Factors
D010293:Pargyline; D009638:Norepinephrine; D013747:Tetrabenazine