Influence of kynurenine treatment on open-field activity, elevated plus-maze, avoidance behaviors and seizures in rats.
In the present studies the effects of single and daily repeated injections of kynurenine were investigated in different behavioral tests in rats. In open-field behavior a single injection of kynurenine decreased rearing activity, while the effect was more pronounced after repeated injections. Similarly, in the elevated plus-maze, kynurenine attenuated the total number of entries in the four arms of the equipment, and after chronic treatment decreased the time spent in the open arms (control: 24%; kynurenine 100 mg/kg: 16%; kynurenine 200 mg/kg: 13%). Kynurenine did not influence the passive avoidance learning paradigm (learning session and avoidance latency) and the extinction of active avoidance response. Kynurenine slightly attenuated the kainic acid-induced wet dog shakes and forelimb clonic activity with rearing. These findings suggest that kynurenine (especially after repeated peripheral injections) inhibited several behavioral responses of the experimental animals. However, in one type of highly motivated experimental paradigm (fear from the foot shock), behavioral depression was not detectable.
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Neurology Services, Massachusetts General Hospital, Boston 02114.
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D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D005106:Exploratory Behavior / Q000187:drug effects*; D007608:Kainic Acid / Q000037:antagonists & inhibitors; D007737:Kynurenine / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000139:chemically induced / Q000188:drug therapy*
D007737:Kynurenine; D007608:Kainic Acid