Amine repletion in the reserpinized cat: effect upon PGO waves and REM sleep

Selective repletion of 5-HT and catecholamines in the reserpinized cat was used to study the role of these biogenic amines in the regulation of PGO wave activity and sleep. The results include: 1. Repletion of 5-HT, following injections of D, L and L-5-HTP, suppressed PGORes in the pons and visual system. A consistent relationship between drug dose and duration of suppression was established. D-5-HTP failed to influence PGORes. L and D, L-5-HTP also induced a state closely resembling slow wave sleep and this change corresponded, temporally, with the period of wave suppression. 2. Repletion of catecholamined, following injections of L-DOPA, often caused behavioral arousal and a conversion from PGORes to PGOW. The molar dose of L-DOPA required to block PGORes was 10-20 times greater than that of L-5-HTP required for a comparable effect. In some cases, L-DOPA failed to arouse the cat, and in each of these instances, it failed to suppress PGORes. 3. L-DOPA consistently failed to induce a premature return of REM sleep in the reserpinized animal. These results suggest that 2 neuronal systems, one employing 5-HT and the other catecholamines, play a part in the regulation of PGORes, and presumably, PGOrem. The 5-HT system may be primarily responsible for suppressing PGOrem during slow wave sleep, with the catecholamine system playing a comparable part during wakefulness. Earlier reports that L-DOPA induces REM sleep in the reserpinized animal were not confirmed, indicating that the postulated role of catecholamines in the induction of this state should be reevaluated.