Effects of intrathecal administration of 8-OH-DPAT on genital reflexes and mating behavior in male rats

A Pivotal Role of Lumbar Spinothalamic Cells in the Regulation of Ejaculation via Intraspinal Connections

“…Hence, it is possible that reflexes producing emissions as noted during the ex copula reflex paradigm are not representative for in copula ejaculatory reflexes. Indeed, contradictory findings with the ex copula paradigm have previously been reported, including inhibitory effects of serotonin 1A receptor agonist 8‐OH‐DPAT, which has inhibitory effects on emissions in the ex copula paradigm [61], while strong facilitative effects on ejaculation latencies in copula [61–65] and induces BCM bursting in the urethrogential reflex model [66]. An alternate explanation for the discrepancy between effects of LSt cell lesions on ejaculatory reflexes in the ex copula paradigm versus the other reflex paradigms used in the present study is that LSt cells may not be essential for emission, but rather for the expulsion phase of ejaculation.…”

A role for 5-hydroxytryptamine in descending inhibition of spinal sexual reflexes

“…Systemic administration of 5 I-IT1B receptor agonists, RU24969 ([5-methoxy-3-(1,2,3,6-tetrahydro-4-pyrinyl (Fernandez-Guasti et al 1989). While, 5-I-IT1A receptor agonists, 8OHDPAT (8-hydroxy-2-(di-n-propylamino)tetraline), ipsapirone or 5-MeODMT (5-methoxytryptamine) facilitate sexual behavior Schnur et al 1989;Lee et al 1990;Ahlenius and Larsson 1991). However, 8OHDPAT suppresses ejaculation and erection ex copula (Schnur et al 1989;Lee et al 1990), although some evidence for reduced seminal plug weight in copula was found suggesting inhibition of ejaculatory mechanisms (Schnur et al 1989).…”

“…While, 5-I-IT1A receptor agonists, 8OHDPAT (8-hydroxy-2-(di-n-propylamino)tetraline), ipsapirone or 5-MeODMT (5-methoxytryptamine) facilitate sexual behavior Schnur et al 1989;Lee et al 1990;Ahlenius and Larsson 1991). However, 8OHDPAT suppresses ejaculation and erection ex copula (Schnur et al 1989;Lee et al 1990), although some evidence for reduced seminal plug weight in copula was found suggesting inhibition of ejaculatory mechanisms (Schnur et al 1989). In addition, 5-HT1A receptor activation also stimulates arousal, which may explain the differential effects seen ex copula and during mating behavior (Lee et at.…”

Central nervous system agents in the treatment of erectile dysfunction: How do they work?

“…The complexity of the regulation of serotonin is well illustrated by the opposite effect of 5-HT1A and B receptor on sexual behavior. The 5-HT1A agonist 8-OH-DPAT, when injected systemically, produces a dramatic facilitation of the male rat ejaculatory behavior [25]. In contrast, the 5-HT1B receptor is thought to inhibit ejaculatory behavior as the increased ejaculation latency produced by 5-hydroxytryptophan is fully antagonized by treatment with the 5-HT1B receptor antagonist isamoltane [26].…”