EXPERIMENTAL-EVIDENCE OF PENILE ERECTIONS DURING PARADOXICAL SLEEP INTHE RAT

WE have developed a new technique to chronically monitor penile erecti ons in the rat across behavioural states. This technique, involving ch ronic erectile tissue pressure monitoring and simultaneous ischiocaver nosus and bulbospongiosus (IC-BS) muscle electromyography, demonstrate s for the first time that rats exhibit penile erections during paradox ical sleep (PS). No erectile events were observed during slow wave sle ep. These PS-related erectile events were similar to visually confirme d, waking state, erections in that they were associated with an increa se in baseline erectile tissue pressure and, with IC-BS muscle bursts, dramatic suprasystolic penile pressure peaks often greater than 1000 mmHg. PS-related erections were 11 +/- 7 s in duration and were observ ed in 28.5% of all PS episodes. This method of chronic penile erection monitoring in the rat provides a new animal model for investigating n eural mechanisms of sleep-related erections.