It is known that penile erection is mediated primarily through the release of a nonadrenergic noncholinergic (NANC) neurotransmitter which has been recently identified as nitric oxide (NO). To evaluate whether the endothelium is involved in neurally mediated relaxation in corpus cavernosum, we determined electrical field stimulation (EFS) induced relaxation in both the presence and absence of endothelium, and we tested the effect of an inhibitor of NO synthase, NG-nitro-L-arginine (NOARG), in the absence of endothelium to examine if de-endothelialized tissue can still generate NO. Isolated corpus cavernosal strips from New Zealand White rabbits were used for isometric tension study using organ chambers. The endothelium was removed through denuding tissue. After the tissue was contracted with norepinephrine, EFS was performed at frequencies of 5, 15 and 40 Hz in the presence of guanethidine and atropine to evaluate NANC-selective nerural relaxation. The relaxation induced by EFS was observed after preincubation with NOARG(10(-4) M) for 30 minutes. L-arginine (10(-3) M) was then added for 30 minutes in the presence of NOARG before a second set of EFS studies were performed. Following norepinephrine precontraction, EFS relaxed corporal strips in both the intact and de-endothelialized strips. However, deendothelialization significantly impaired EFS induced relaxation (p< 0.05). NOARG attenuated relaxation induced by EFS and the addition of L-arginine reversed the inhibitory effect of NOARG in the strips with endothelium. In the strips without endothelium, NOARG still inhibited EFS induced relaxation. This relaxation was reversed by the addition of L-arginine.
Animal ; Endothelium/physiology ; Male ; Muscle Relaxation ; Neurons/metabolism ; Nitric Oxide/*physiology ; *Penile Erection ; Penis/innervation/*physiology ; Rabbits

OBJECTIVETo explicate the spinal nerve source of the rabbit penis cutaneous sensation.

METHODSTwelve adult male rabbits were randomly divided into two groups of equal number. While mechanical stimuli were given to the penis by different von Frey hairs, single fiber activities were recorded in vivo in the left (Group A) and right (Group B) S1-S4 spinal nerves, respectively. The mechanical threshold, adaptability and conduction velocity of the fibers were analyzed.

RESULTSWhen the ipsilateral penis was mechanically stimulated, discharges were detected in S2 and S3 spinal nerve fibers, but not in S1 and S4. The discharge fibers were 39.67 +/- 3.14 (S2) and 21.00 +/- 2.19 (S3) in the left spinal nerve and 40.00 +/- 3.16 (S2) and 19.67 +/- 2.58 (S3) in the right. There was no obvious difference between the numbers of the left spinal nerves and the right ones (P > 0.05).

CONCLUSIONThe rabbit penis cutaneous sensation originates from S2 and S3 spinal nerves.

Animals ; Electrophysiology ; Male ; Neurons, Afferent ; physiology ; Penis ; Rabbits ; Random Allocation ; Sensory Thresholds ; Skin ; innervation ; Spinal Nerves ; physiology

The somatosensory evoked potentials (SEPs), following stimulation of both the posterior tibial nerve (PTSEP) and pudendal nerve (PNSEP), comprise of the lumbar negative, subcortical and cortical potential. These can be used to assess the long somatosensory pathway, including peripheral, intraspinal and intracranial conduction along the entire length. This study aimed to compare the central conduction time between the PTSEP and the PNSEP, and to investigate the relationship between the intraspinal and intracranial conduction time in the SEP pathway. The SEPs following stimulation of the posterior tibial nerve at the ankle and the pudendal nerve at the shaft of the penis were analyzed in 20 normal male subjects. The central conduction of the PNSEP was found to be slower than that of the PTSEP (p <0.05). This difference is due to a delay in conduction rather than that of intracranial conduction.
Adolescence ; Adult ; Evoked Potentials, Somatosensory* ; Human ; Male ; Middle Age ; Neural Conduction* ; Penis/innervation* ; Tibial Nerve/physiology* ; Time Factors

OBJECTIVETo evaluate the application of intracavernous pressure (ICP) monitoring in the electrophysiologic and pharmacologic induction of penile erection.

METHODSThe penile dorsal nerves (DN) of 8 anesthetized adult male rats were isolated and the corpora cavernosa exposed. A heparinized 25-gauge angiocath (intravenous catheter) was inserted into the right corpus cavernosum to monitor the ICP and a 30-gauge needle was inserted into the left corpus cavernosum for intracavernosal drug administration. Penile erection was induced by electrical stimulation of the dorsal nerve (16 Hz frequency, 0.5 ms pulse width, 20 s duration, 4 volts) and intracavernous papaverine hydrochloride injection (0.4 mg). ICP was recorded with the SMUP-PC biological signal process system.

RESULTSIn the anesthetized rats, the baseline level of ICP was (12.3 +/- 3.1) mm Hg and the electrical stimulation of the DN significantly increased ICP[(36.4 +/- 2.3) mm Hg, P < 0.05], which slowly returned to baseline pressure after termination of the electrical stimulation. The intravavernosal administration of papaverine also induced a significant increase in ICP [(28.4 +/- 6.1) mm Hg, P < 0.05].

CONCLUSIONICP monitoring in rats provides a useful scientific tool for in vivo studies of penile erection in experimental rat models. It is of great significance for further studying the physiology of penile erection and the pathogenesis of erectile dysfunction as well as for evaluating the efficacy of novel therapies for erectile dysfunction.

Animals ; Electric Stimulation ; Injections ; Male ; Papaverine ; administration & dosage ; pharmacology ; Penile Erection ; drug effects ; physiology ; Penis ; innervation ; Rats ; Rats, Sprague-Dawley

Trauma and surgery sometimes cause erectile dysfunction because of injury to pelvic nerves and cavernous nerves of the penis. The ideal treatment is to make the injured nerves regenerate themselves and erectile function recover completely. This paper reviews the recent advances in the studies of erigentes regeneration and plerosis following injury in order to find the best method to enhance erigentes regeneration.
Erectile Dysfunction ; therapy ; Humans ; Male ; Penile Erection ; physiology ; Penis ; innervation ; Peripheral Nerve Injuries ; Regeneration ; Transurethral Resection of Prostate ; adverse effects

OBJECTIVETo investigate the effects on erectile function of transplanted major pelvic ganglion into the corpus cavernosum of adult male rats undergoing transection of bilateral cavernous nerves.

METHODSTwenty-six male Sprague-Dawley rats (3 - 4 month-old and 300 - 400 g/each) were divided into 2 groups: experimental group (transection of bilateral cavernous nerves and transplantation of left ganglion into left crus of penis, n = 16) and control group (transection of bilateral cavernous nerves only, n = 10). Erectile function was measured by injecting APO, and intracavernous pressure was measured 1 and 3 months afterwards by electric-stimulating the right major pelvic ganglion or the left crus. Half animals in each group were sacrificed 1 and 3 months afterwards for detecting nNOS-containing nerve fibers of corpus cavernosum. Electron microscopy of the implanted area was performed to assess neuronal survival.

RESULTSBoth of the two groups have no erectile response to APO injection. Electrostimulation on the right major pelvic ganglion and left crus failed to produce erection in experimental group. The mean pressure changes in the two groups, measured by stimulating the left crus, were (9.41 +/- 3.20) and (4.16 +/- 2.58) cmH(2)O 1 month afterwards, and (13.67 +/- 4.18) and (5.09 +/- 2.74) cmH(2)O 3 months afterwards, respectively (P < 0.05). An increased number of nNOS-containing nerve fibers in left crus was detected in experimental group 1 and 3 months later, compared with control one (218.7 +/- 24.5, 18.0 +/- 3.7; 183.2 +/- 19.7, 19.0 +/- 3.8; P < 0.05). Ultrastructure examination by transmission electron microscope confirmed the survival of the implanted ganglion.

CONCLUSIONMajor pelvic ganglion can survive in the corpus cavernosum, and it has significant effects on the number of nNOS-containing nerve fibers and the alteration of intracavernous pressure.

Animals ; Autonomic Denervation ; Celiac Plexus ; surgery ; Ganglia, Autonomic ; transplantation ; Graft Survival ; Male ; Nitric Oxide Synthase ; metabolism ; Penile Erection ; physiology ; Penis ; innervation ; surgery ; Rats ; Rats, Sprague-Dawley ; Transplantation, Autologous

OBJECTIVESTo observe the cavernosal nerve dysfunction of diabetic Sprague Dawley rats.

METHODSThirty-five Sprague-Dawley rats were divided randomly into diabetes model group(n = 25) and normal group(n = 10). Diabetes model was established by administration of streptozotocin (63 mg/kg) in single intraperitoneal dosing. Giving single wave stimulus, corpus cavernosal nerve was measured for its latent period of reaction and myopotential.

RESULTSCompared with other groups, diabetic rats had longer reflection latent period(P < 0.01) and higher corpus cavernosum smooth muscle myopotential (P < 0.01).

CONCLUSIONSThe results indicate that corpus cavernosal nerve dysfunction may play an important role in the erectile dysfunction of diabetic rats.

Animals ; Diabetes Mellitus, Experimental ; complications ; physiopathology ; Erectile Dysfunction ; etiology ; Evoked Potentials ; Male ; Nitric Oxide ; physiology ; Penis ; innervation ; Rats ; Rats, Sprague-Dawley ; Streptozocin

OBJECTIVETo assess the clinical significance of electrophysiological tests of bulbocavernosus reflex (BCR), ischiocavernosus reflex (ICR) and pudenda somatosensory evoked potential (PSEP) for patients with erectile dysfunction (ED).

METHODSElectrophysiological tests of BCR, ICR and PSEP were performed for 232 ED patients with IIEF-5 scores of 2-20 (10.39 +/- 5.52), another 21 normal volunteer controls underwent the same tests, and the results were compared.

RESULTSAbnormal results, such as prolonged and advanced latencies, were found in 94 (40.5%) of the patients, which suggested neurotic ED with different degrees of cauda equine nerve injuries.

CONCLUSIONElectrophysiological tests of BCR, ICR and PSEP can objectively reveal the functional state of the cauda equine nerve and offer an important support to the diagnosis of nerve-mediated ED.

Adult ; Aged ; Case-Control Studies ; Electrophysiology ; Erectile Dysfunction ; physiopathology ; Evoked Potentials, Somatosensory ; Humans ; Male ; Middle Aged ; Muscle, Smooth ; physiopathology ; Penis ; innervation ; physiopathology ; Reflex ; physiology

OBJECTIVETo investigate the effect of FK506 on the cavernous nerve regeneration after injury and to discuss its possible action mechanisms.

METHODSFifty-four male adult Sprague-Dawley rats were randomized into three groups: Group 1 (sham control), Group 2 (unilateral cavernous nerve ablation), and Group 3 (unilateral cavernous nerve ablation with subsequent injection of FK506). Electrostimulation of the cavernous nerve was performed at 1 and 3 months after surgical injury. The intracavernous pressure was continuously detected and the rats were followed by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) staining to identify NOS in the penile nerve fibers of the penile shaft.

RESULTSAt 1 month, the number of NOS-positive nerve fibers significantly decreased with no statistical difference among the three groups except the sham controls (P > 0.05). At 3 months, electrostimulation revealed greater maximal intracavernous pressure in Group 3 than in Group 2 (P < 0.01). Furthermore, the number of NOS-positive nerve fibers showed a significant increase (P < 0.01), but not in Group 2 (P > 0.05).

CONCLUSIONFK506 injection enhances the regeneration of cavernous nerves after injury and the recovery of erectile function in rats.

Animals ; Electric Stimulation ; Male ; Nerve Fibers ; enzymology ; physiology ; Nerve Regeneration ; drug effects ; Nitric Oxide Synthase ; analysis ; Penile Erection ; drug effects ; Penis ; innervation ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tacrolimus ; pharmacology

OBJECTIVETo study the relationship between substance P (SP) and/or calcitonin gene-related peptide (CGRP) immunoreactive neurons in dorsal root ganglia (DRG) and the transmission of nociception in the penile frenulum of rats.

METHODSThe fluoro-gold (FG) retrograde tracing method was used to trace the origin of nerve terminals in the penile frenulum of rats. And SP and/or CGRP immunofluorescence labeling was employed to detect the distribution of SP and/or CGRP immunoreactive neurons in DRG.

RESULTSFG retrograde tracing showed that the FG retrolabeled neurons were localized in L6-DRG and S1-DRG. SP and/or CGRP immunofluorescence labeling indicated that a large number of DRG neurons were SP- and CGRP-immunoreactive, different in size, bright red and bright green respectively in color, and arranged in rows or spots among nerve bundles. All the FG/SP and FG/CGRP double-labeled neurons were medium or small-sized. One third of the FG-labeled neurons were SP-immunoreactive, and a half of them CGRP-immunoreactive in L6-DRG and S1-DRG respectively. The FG/SP/CGRP-labeled neurons accounted for one fifth of the FG retro labeled neurons.

CONCLUSIONSP- and CGRP-immunoreactive neurons in L6-DRG and SI-DRG of rats may be involved in the transmission of nociception in rat penile frenulum.

Animals ; Calcitonin Gene-Related Peptide ; analysis ; Ganglia, Spinal ; chemistry ; cytology ; Male ; Microscopy, Fluorescence ; Neurons ; chemistry ; physiology ; Neurons, Afferent ; chemistry ; physiology ; Penis ; innervation ; Rats ; Rats, Sprague-Dawley ; Substance P ; analysis