Facilitation and inhibition of the urethrogenital reflex in spinal cord-transected rats

Increase of the Ejaculatory Potency by the Systemic Administration of Aqueous Crude Extracts of Cihuapatli (Montanoa Genus) Plants in Spinal Male Rats

In the present study, evidence on the aphrodisiac activity of Montanoa frutescens and Montanoa grandiflora and a comparison with the aphrodisiac activity of Montanoa tomentosa is presented. By using the fictive ejaculation model in spinal male rats, electromyographic recordings of the genital motor pattern of ejaculation were obtained in the bulbospongiosus muscles and analyzed after the intravenous injection of aqueous crude extracts of Montanoa tomentosa, Montanoa frutescens, and Montanoa grandiflora. Results showed that the systemic administration of the aqueous crude extracts of Montanoa plants elicits a significant increase in the ejaculatory capacity of spinal male rats with very robust ejaculatory motor patterns that included the expression of tonic penile erections and penile movements and the potent expulsion of urethral contents. In conclusion, Montanoa frutescens and Montanoa grandiflora increase the ejaculatory potency with aphrodisiac activity similar to Montanoa tomentosa.

Sexual outcomes after organ potency-sparing surgery and glans reconstruction in patients with penile carcinoma

INTRODUCTION

Radical surgery is the "gold standard" for treatment of invasive penile carcinoma but very poor aesthetic, functional and psychological outcomes have been reported. Our purpose was to assess the impact of organ potency-sparing surgery in locally confined carcinoma of the penis.

MATERIALS AND METHODS

We evaluated retrospectively 42 patients with early penile cancer (Ta,T1,T2), treated with glandulectomy and glanduloplasty with urethral mucosa and sparing of cavernosal apexes, or glandulectomy and limited apical resection in cases of Stage T2. Sexual function, ejaculation and libido were evaluated with an IIEF-15 questionnaire before the appearance of neoplasia (about three months before the surgery) and six months after surgery. Quality of life was evaluated by the Bigelow-Young questionnaire. The scores relating to two weeks prior to the surgery have been compared to those obtained six months after surgery. The statistical analysis was conducted using t-Student for repeated measures and analysis of variance.

RESULTS

Six months after surgery 73% of patients reported spontaneous rigid erections, 60% coital activity while 76% of the group treated with urethral glanduloplasty reported normal ejaculation and orgasm, regained an average of 35 days after surgery. The average IIEF-15 scores reported in the entire series in the domains of erection, libido and coital activity of the pre-cancer period were not statistically different than those recorded six months after surgery. In the group treated with glandular reconstruction, pre-and postoperative IIEF-15 mean scores related to ejaculation and orgasm domains were not significantly different. Mean scores of Bigelow-Young questionnaires related to sexual pleasure, familial, social and professional relationships showed significant improvement after surgery.

CONCLUSIONS

Potency sparing-sparing surgical treatments have a positive impact on a wide spectrum of the patient's life including family relationships, and social and working conditions.

Pro-sexual effects of Turnera diffusa Wild (Turneraceae) in male rats involves the nitric oxide pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Turnera diffusa Wild has been used in folk medicine by its aphrodisiac and tranquilizing properties. Previously we experimentally showed the aphrodisiac effect of a chemically characterized aqueous extract of Turnera diffusa in male rats. However, the mechanism of action underlying such effects has not been studied.

STUDY AIMS

As part of our systematic studies of pharmacological properties of Turnera diffusa, we aimed to analyze whether the increased sexual motivation and the augmented sexual performance of sexually sluggish (SL) male rats treated with Turnera diffusa involves the NO pathway. Additionally we analyzed whether such effects were exerted at the level of the brain or the spinal cord. Finally, anxiety levels and ambulatory activity were also evaluated.

MATERIAL AND METHODS

Turnera diffusa (10-40 mg/kg) and sildenafil citrate (10 mg/kg) with or without a nonspecific inhibitor of NO synthase, Nω-nitro-L-arginine methyl esther (L-NAME, 12.5 mg/kg) were evaluated in SL rats, in a standard sexual behavior test and in the fictive ejaculation model in spinal cord transected and urethane-anaesthetized SL rats. Anxiety levels or ambulation were assessed in the burying behavior and open-field tests.

RESULTS

Turnera diffusa and sildenafil (both at 10 mg/kg) facilitated expression of male sexual behavior by shortening mainly ejaculation latency. Treatments also facilitated the number of discharges in the ejaculatory motor pattern as well as the number of ejaculatory motor patterns and its associated penile erections. L-NAME prevented the pro-sexual effects of treatments on both experimental models. Besides, the extract of Turnera diffusa (10 mg/kg) produced an anxiolytic-like effect in male rats without affecting ambulation.

CONCLUSIONS

Findings from the present work support the notion that pro-sexual effect of the aqueous extract of Turnera diffusa in rats involves the participation of NO pathway, mainly at central level. The anxiolytic-like effect of Turnera diffusa is an advantage to its use for improving sexual performance.

Muscarinic receptor antagonism at the spinal cord level causes inhibitory effects on male rat sexual behavior

The role of cholinergic neurotransmission in male rat sexual behavior at the brain level has been studied by several researchers. However, little is known about its role at the spinal cord level. In this study, the effects of the intrathecal (IT) administration of the muscarinic receptor antagonist subtypes (MRAs) methoctramine (Meth), tropicamide (Trop) and 4-DAMP on male rat sexual behavior were evaluated during three ejaculatory series. Meth and Trop are preferring antagonists for the M2/M4 receptor subtypes, and 4-DAMP is a preferring antagonist for the M3 receptor subtype. All the MRAs tested noticeably inhibited male rat copulatory behavior, reflected by a reduction in the number of animals engaging in sexual behavior and a gradual decrease in the number of animals able to ejaculate. Significant increases in intromission latency (IL), ejaculation latency (EL) and post-ejaculatory interval (PEI) were observed. The ranking of inhibitory potency in all recorded parameters was Meth>/=4-DAMP>Trop. In theory, the effects of Meth and Trop could be a result of interaction with M2/M4 receptors. However, given that the M2 receptor constitutes the greatest population of muscarinic receptors at all spinal cord sites and given the high affinity for Meth on M2 receptors, the high potency in the inhibitory effects of Meth is indicative of the special role of M2 spinal receptors in the implementation of this behavior. The weaker effects of Trop could be linked to the smaller population of M4 receptors in the spinal cord, but some interaction with M2 receptors is probable. Since some differences in the pattern of inhibitory response between Meth and 4-DAMP were observed in this and a previous study, a possible role for M3 receptors must be considered. The data obtained in this study confirm the facilitating effect of acetylcholine (ACh) at the spinal cord level on male rat sexual behavior through muscarinic mechanisms, with an important influence on ejaculatory processes. These data support the hypothesis of the modulating role of ACh on male rat sexual behavior at the spinal cord level.

Cholinergic facilitation of erection and ejaculation in spinal cord-transected rats

Penile reflexes (PRs) were monitored in chronic spinal cord-transected rats by identifying them visually, and at the same time they were recorded as the electromyographic activity of bulbospongiosus muscles. Intraperitoneal injection of the agonist muscarine (10 microg) produced a facilitation of PRs. A decrease in the latency, an increase in the number of clusters and often an increase in the duration of cups were found after muscarine. In addition, 66% (six out of nine) of the animals ejaculated after muscarine. These results suggest that cholinergic receptor stimulation may be involved in erectile and ejaculatory mechanisms mediated by the spinal cord.

Muscarinic mediation of the urethro genital reflex in spinal cord-transected rats

The effects of muscarinic receptor stimulation were tested on the urethro genital reflex (UGR) in anesthetized and spinal cord-transected rats. Drugs were applied directly to the spinal cord. The electromyographic activity (EMG) of the bulbospongiosus (BS) muscle was used for recording UGR. In six animals BS as well as soleus, posterior biceps or peroneus tertius muscle EMG was recorded simultaneously. Muscarine (5, 10, 20, 50 and 100 microg) was applied in 22 animals after cutting L6-S1 dorsal roots. Some observations were made on another six animals, to which an extensive bilateral dorsal rhizotomy (L3-S2) was performed. Rhythmic bursts of similar frequency and size to those seen during UGR were found in BS muscle a few minutes after muscarine application. No rhythmic bursting was found on the hindlimb muscles, but exclusively on BS muscles. The effects of homatropine (25, 50, 100 and 200 microg), an acetylcholine muscarinic receptor antagonist, were tested in 21 rats after UGR was elicited three times at low stimulation intensity (7 mm Hg). Homatropine produced two effects: (i) A significant increase in the latency of UGR. (ii) A facilitation of UGR inhibition. In view of these results it can be speculated that muscarinic receptor stimulation is involved in the elicitation of UGR.