The Rat as a Model for the Study of Penile Erection

Quinlan, David M.; Nelson, Randy J.; Partin, Alan W.; Mostwin, Jacek L.; Walsh, Patrick C.

doi:10.1016/s0022-5347(17)40926-8

Cited by 176 publications

(112 citation statements)

References 28 publications

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“…The major pelvic ganglion, cavernous nerves and pelvic organs were exposed. 15 The skin overlying the penis was incised, and the right penile crus was exposed by removing part of the overlying ischiocavernous muscle. A 23-gauge needle ®lled with 250 Uaml heparin solution and connected to PE-50 tubing was inserted into the crus and ®xed to the tunica with a 7-zero Dermalone suture.…”

Section: Functional Evaluation and Tissue Procurementmentioning

confidence: 99%

The role of growth factor on regeneration of nitric oxide synthase (NOS)—containing nerves after cavernous neurotomy in the rats

et al. 1999

Int J Impot Res

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Nitric oxide synthase (NOS) containing nerve regeneration can be seen six months after unilateral cavernous nerve neurotomy in rats. However its molecular mechanism is still unknown. It is believed that growth factors are involved in this phenomenon. In this study we investigated the change of NOS containing nerve ®bers and the RNA expression of insulin like growth factor (IGF)-I, nerve growth factor (NGF), transforming growth factor (TGF)-a, TGF-b 1 , TGF-b 2 . TGF-b 3 and NOS on the penis after cavernous nerve neurotomy in rats.Male rats were divided into three groups: (1) sham operation (N 10); (2) unilateral neurotomy of a 5 mm segment of the cavernous nerve (N 15); and (3) bilateral neurotomy (n 15). Electrostimulation of the intact cavernous nerve or pelvic ganglion was performed at one, three and six months. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining was used to identify NOS in the penile nerve ®bers. The gene expression for growth factors and bNOS was investigated in corporal tissue by reverse transcriptase-polymerase chain reaction (RT-PCR) using speci®c oligonucleotide primers.One month after neurotomy, both unilateral and bilateral neurotomy groups showed a signi®cant decrease in NOS-containing nerve ®bers on the dorsal and intracavernosal nerves on the side of neurotomy, and a signi®cantly lower mRNA expression of bNOS, IGF-I and TGF-b 2 . At three months, the number of NOS-containing nerve ®bers in the unilateral neurotomy group increased only slightly but at six months those in the intracavernosal nerve increased in a signi®cant amount (P`0.0001), however mRNA expression of bNOS, IGF-I and TGF-b 2 showed a signi®cant increase as early as at three months. After bilateral neurotomy, the NOS-positive nerve ®bers in the dorsal and intracavernosal nerve were signi®cantly decreased at one month and remained so at six months; no erectile response could be elicited by pelvic ganglion stimulation. In the unilateral neurotomy group at six months, more NOS-positive neurons in the pelvic ganglia were found on the intact side than on the side of the neurotomy (P`0.003), indicating that the regeneration derives from pelvic ganglion neurons on the intact side. Furthermore, electrostimulation in the unilateral neurotomy group revealed a greater maximal intracavernosal pressure and a shorter latency period at six months than at one month (P`0.014, P`0.001, respectively).These data suggest that IGF-I and TGF-b 2 may play a key role in regeneration of NOS-containing nerve ®bers in the dorsal and intracavernosal nerves after unilateral cavernous nerve injury.

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Section: Functional Evaluation and Tissue Procurementmentioning

confidence: 99%

The role of growth factor on regeneration of nitric oxide synthase (NOS)—containing nerves after cavernous neurotomy in the rats

et al. 1999

Int J Impot Res

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“…In another functional study, in which penile erection was induced either by apomorphine or pelvic nerve stimulation, the ICP response also remained after chronic cavernous nerve ablation. 23 Prior to the aforementioned reports, and our more recent data reported herein, it had been shown that bilateral cavernous nerve ablation almost totally eliminated visible penile erection, 8,9 leading to the mistaken impression that the cavernous nerve made the most physiologically relevant contribution to penile erection. Our data are not inconsistent with these previous observations, as we have noted that an ICPaBP ratio of greater than 0.5X0.6 ratio is required for a visible penile erection; smaller increases in ICPaBP produce only penile tumescence, but not obvious penile erection (unpublished data).…”

Section: Discussionmentioning

confidence: 69%

“…7 However, other reports showed that bilateral transection of the main penile nerve (cavernous nerve) eliminated visible penile repose in those animals. 8,9 As such, the goal of this study was to evaluate the physiological contribution of ancillary penile nerves to penile erection in a well-established rat model in vivo. To this end, we used electrical stimulation of the midial preoptic area (MPOA), and the normal evoked erectile response to that stimulus, to evaluate the effects of transection of the cavernous nerves (main penile nerves) on the intracavernous pressure (ICP) response.…”

Section: Introductionmentioning

confidence: 99%

Significant physiological roles of ancillary penile nerves on increase in intracavernous pressure in rats: experiments using electrical stimulation of the medial preoptic area

et al. 2001

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The objectives of this work were to evaluate the contributions of the ancillary penile nerves to penile erection in male rats in vivo. We investigated the effects of unilateral and bilateral transection of the cavernous nerve (main penile nerve) on the increase in intracavernous pressure (ICP) following electrical stimulation of the medial preoptic area (MPOA) in male rats in vivo. After unilateral or bilateral transection of the cavernous nerve (main penile nerve), the ICP responses showed decreases of 28% and 55%, respectively compared to those ICP responses before transection. In other words, even after bilateral transection of the cavernous nerve, signi®cant increases in the ICP response following central stimulation were observed. In contrast to these ®ndings, the ICP response was completely eliminated following bilateral pelvic nerve transection. These data suggested that the ancillary penile nerves, which originate from the major pelvic ganglia, have a complementary role to the cavernous nerves in the autonomic motor innervation of the penis.

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“…A rat model of erection induced by electric stimulation of the cavernous nerve was first developed by Quinlan et al, in 1989. 3 Although the rat model of erection has been utilized at various institutions, 4 -7 the method of electric stimulation varies study by study. To establish a reproducible method of electric stimulation, we performed a preliminary experiment of bilateral electric stimulation of the cavernous nerve.…”

Section: Electric Stimulationmentioning

confidence: 99%

The effect of sildenafil on electrostimulation-induced erection in the rat model

et al. 2002

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This study was conducted to show the effect of sildenafil on electrostimulation-induced erection in the rat model. Fifteen 12-week-old male Wistar Kyoto rats were used. The intracavernous pressure and arterial blood pressure were simultaneously monitored through electric cavernous nerve stimulation before and after the administration of sildenafil (2 mg=kg). Statistical analysis was performed on maximal intracavernous pressure (MIP), mean arterial blood pressure (MAP), the MIP=MAP and detumescence time. MAP decreased significantly by about 20 mmHg after sildenafil administration. The MIP=MAP increased significantly after sildenafil administration. The effect of sildenafil on the MIP=MAP was marked especially at lower (2 -3 Hz) frequencies. The detumescence time significantly increased after sildenafil administration. We have shown that sildenafil is effective for enhancing erection at lower frequencies and prolonging penile erection in rats. After the administration of sildenafil, penile erection would be induced by weak stimuli that will not cause penile erection under normal conditions.

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The Rat as a Model for the Study of Penile Erection

Cited by 176 publications

References 28 publications

The role of growth factor on regeneration of nitric oxide synthase (NOS)—containing nerves after cavernous neurotomy in the rats

The role of growth factor on regeneration of nitric oxide synthase (NOS)—containing nerves after cavernous neurotomy in the rats

Significant physiological roles of ancillary penile nerves on increase in intracavernous pressure in rats: experiments using electrical stimulation of the medial preoptic area

The effect of sildenafil on electrostimulation-induced erection in the rat model

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