Principal mechanisms controlling penile retraction and protrusion in rabbits

Sjöstrand, Nils O.; Klinge, Erik

doi:10.1111/j.1748-1716.1979.tb06390.x

Cited by 119 publications

(84 citation statements)

References 33 publications

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“…Even after extensive adrenergic denervation, a few fibers around critical resistance vessels (helicine arteries) may have a powerful effect on penile blood flow. Sjöstrand and Klinge (1979) posited that, owing to the thick muscular walls of the helicine vessels and their narrow lumen, even a low adrenergic input may have a profound influence on penile blood flow. Apparently, a modest adrenergic tone (0.2 Hz) is sufficient to maintain penile retraction and flaccidity in the rabbit (Sjös-trand and Klinge, 1979).…”

Section: Discussionmentioning

confidence: 99%

“…Adrenergic input functions in terminating erection (detumescence) and maintains penile flaccidity by providing a tonic inhibitory discharge to penile smooth muscle (Sjöstrand and Klinge, 1979;Giuliano et al, 1993). The adrenergic innervation of the penis arises from neurons in the sympathetic chain ganglia Dail et al, 1989) and, as depicted in schematic diagrams of penile neural cir-cuitry Giuliano et al, 1995a), may reach the penis by traversing the pudendal (PudN), HN, and the pelvic nerves (PN).…”

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confidence: 99%

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The sensory branch of the pudendal nerve is the major route for adrenergic innervation of the penis in the rat

1997

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

The sensory branch of the pudendal nerve is the major route for adrenergic innervation of the penis in the rat

1997

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“…As shown in previous horseradish peroxidase studies in dogs [9], the cavernous nerve fibers are connected to central ganglion cells in the spinal cord at the level of T12-L3 (sympathetic centers) and S1-$3 (parasympathetic centers Previous reports on the effects of sympathetic nerve stimulation on penile erection are contradictory [1,4,14,15]. This study was undertaken to clarify intracavernous pressures changes during erection and detumescence induced by neurostimulation of the sympathetic and parasympathetic system.…”

Section: Abstract: Sympathetic Trunks -Erection -Detumescence -Impotmentioning

confidence: 99%

“…However, stimulation of the peripheral stumps of the hypogastric nerves led to a quicker decrease of erection induced by nervi erigentes stimulation. Sj6s-trand and Klinge [ 15] reported a vasoconstrictor pathway to the penis by stimulation of the sacrococcygeal part of the sympathetic trunk and a vasodilatator pathway by stimulation of the hypogastric nerves in rabbits.…”

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confidence: 99%

The sympathetic role as an antagonist of erection

et al. 1991

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Summary. The effects of the lumbar and pelvic sympathetic system on penile erection were studied in a canine model. Erection was induced by cavernous nerve stimulation and detumescence by sympathetic trunk stimulation. Erection induced by cavernous nerve stimulation normally subsides slowly. After discontinuation of electrical stimulation the intracavernous pressure drops within a mean of 291 s to 50% and after a mean of 372s to 10% of the highest level. However, stimulation of the sympathetic trunk at the level of L4-S 1 applied directly after discontinuation of cavernous nerve stimulation accelerated this drop of intracavernous pressure significantly: to 50% after a mean of t9s and to 10% after a mean of 36s. If stimulation of the sympathetic trunk was initiated 20 s before cavernous nerve stimulation, the pressure rise was aborted completely. Neurostimulation of the hypogastric nerves alone or in combination with cavernous nerve stimulation did not change the intracavernous pressure. These results were not altered after neurotomy of the pudendal or hypogastric nerves. The main pathway of the fibers from the sympathetic trunk to the penis seems to run via the pelvic plexus. The stimulation voltage and frequency to induce erection or detumescence were equivalent. Our results suggest that an elevated central sympathetic tone may be one of the causes of psychogenic impotence. Key words: Sympathetic trunks -Erection -Detumescence -ImpotenceThe erectile tissue of the corpora cavernosa is under the control of the parasympathetic and sympathetic nervous systems [11]. As shown in previous horseradish peroxidase studies in dogs [9], the cavernous nerve fibers are connected to central ganglion cells in the spinal cord at the level of T12-L3 (sympathetic centers) and S1-$3 (parasympathetic centers Previous reports on the effects of sympathetic nerve stimulation on penile erection are contradictory [1,4,14,15]. This study was undertaken to clarify intracavernous pressures changes during erection and detumescence induced by neurostimulation of the sympathetic and parasympathetic system. Materials and methods Animal preparationsThe experiments were carried out on fourteen mongrel dogs (18-29 kg). The dogs were premedicated with acepromazine 0.1 mg/kg and ketamine 5 mg/kg intramuscularly and anesthesized by intravenous administration of pentobarbital (100-130mg as a bolus; maintenance with additional 10 mg dosages as required). All animals were breathing spontaneously. Intravenous saline perfusion was given 2 ml-kg -l" h -1. After all preparations and surgical exposures the dogs were anticoagulated with sodium heparin (1,000U as a bolus; maintenance 100 U/h) to prevent blood clots inn the recording lines. Surgical proceduresThe dogs were placed in the supine position. The abdomen was entered via a midline incision. The midshaft of the penis was dissected free from skin and subcutaneous tissue. After dissection of the perivesical fat, bipolar cuff electrodes (Avery Lab) were placed around both cavernous nerves. The same elect...

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“…Erection stimulatory techniques have included electrical stimulation of pelvic nerves supplying the penis, 1 in copula natural erection contexts, 31 ex copula penile re¯exive stimulation, 6,31 peripheral pharmacological stimulation, 24 central pharmacological stimulation, 32,33 sleeprelated tests of erectile phenomena, 34 noncontact pheromonal stimulation, 35 and electrical stimulation of central nuclei associated with erectile responses. 36 Erection monitoring techniques have included observation and counting phenomenal erections, 32 penile plethysmography, 37 penile dimensional measurements, 38 video recording erections, 21 radionuclide penile scintigraphy, 39 intracavernous pressure measurements with transducers, 9,23 intracavernosal blood¯ow recording by laser Doppler owmetry, 40 telemetric intracavernous pressure recordings in the conscious animal, 34,41 and combinations of monitoring techniques to determine the involvement of exact neural mechanisms during different erectile contexts. 42 …”

mentioning

confidence: 99%

General use of animal models for investigation of the physiology of erection

Burnett

2001

Int J Impot Res

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Animals have consistently assumed a major place in the scienti®c developments of erection physiology, and in fact the use of animal models can be claimed to have inaugurated this ®eld as a true scienti®c discipline. The roots of the science of sexual medicine do not coincide with its practice, which conceivably pertains to aphrodisiacs and other sexual stimulants touted as therapies since antiquity. Rather, the beginnings of scienti®c study in the ®eld are ®ttingly identi®ed with the pioneering experimental work of Eckhard, who in 1863 showed the importance of the pelvic nerves for erectile function by performing electrical stimulation of these`nervi erigentes' in the anesthetized dog to elicit penile erection. 1 The understanding that penile erection is displayed under neurophysiological control was con®rmed and re®ned towards the late nineteenth century by the work of several important researchers in the ®eld, including Mu È ller, Bernard, Gaskell, and Langley and Anderson, who applied animal models to show the gross anatomic locations and physiological relevance of nerves coursing from spinal levels to the pelvis for regulation of penile erection: the mostly antagonistic parasympathetic and sympathetic autonomic nerves, and the somatic nerves. 2,3 The impressive methods of electrophysiological experimentation in the mammalian pelvis combined with extirpative lesioning of spinal out¯ow tracts employed by many of these early scientists continue to be applied similarly in modern research studies.Other pre-eminent control systems involved in erection physiology, accepted now as basic tenets of the ®eld, are known substantially from animal experimentation. The physiology of genital blood ow as an essential component of the erectile response was discovered early and established in concert with electrophysiological investigation. Research progress in recent decades has built on observations of the role of the vascular system and taken a major focus towards understanding penile vascular smooth muscle properties and penile hemodynamics. The central nervous system control of penile erection has been explored somewhat less intensively thus far, although early neuropharmacological and lesioning methods have suggested that hypothalamic and limbic pathways exert predominant in¯uences in the erectile response. 2,4,5 Scienti®c study in animals has also supported the erection regulatory basis involving circulating male hormones, evidenced by the fact that androgen loss such as that following castration leads to erectile impairment and, oppositely, androgen replacement promotes recovery of erectile function. 6,7 Role of animal models to study penile erectionThe selection of animal models for study in the ®eld of sexual dysfunction research has undergone an evolutionary process much like the ®eld itself. The relatively large size and thus inherent technical feasibility of certain animals such as dogs and monkeys lent these species as the primary models for in vivo investigation of penile erection until recent times. Thei...

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Principal mechanisms controlling penile retraction and protrusion in rabbits

Cited by 119 publications

References 33 publications

The sensory branch of the pudendal nerve is the major route for adrenergic innervation of the penis in the rat

The sensory branch of the pudendal nerve is the major route for adrenergic innervation of the penis in the rat

The sympathetic role as an antagonist of erection

General use of animal models for investigation of the physiology of erection

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