RESUMO
Vasoactive intestinal polypeptide was localized by immunocytochemical techniques in the major pelvic ganglion and penile erectile tissue of the rat. Vasoactive intestinal polypeptide fibers were concentrated in penile crura with the density of innervation decreasing distally. The helicine arteries were very densely innervated while fewer fibers surrounded the deep artery of the penis. Intrinsic smooth muscle of the cavernous bodies received a moderate supply of vasoactive intestinal polypeptide immunoreactive fibers. Dorsal vascular structures, including the deep dorsal vein were innervated by vasoactive intestinal polypeptide fibers. Vasoactive intestinal polypeptide immunoreactive cell bodies were found in the major pelvic ganglion, concentrated on one end of the ganglion. Retrograde studies with a dye injected into the penile crura indicated that neurons in major pelvic ganglion projected to the penis. Combined dye and immunofluorescent studies showed that all the dye-labeled neurons were immunoreactive for vasoactive intestinal polypeptide. It is concluded that all vascular beds in the penis of the rat are innervated by vasoactive intestinal polypeptide fibers and that the extent of the innervation is related to the occurrence of smooth muscle. Neurons in the major pelvic ganglion probably are the main source of vasoactive intestinal polypeptide fibers to the penis.
Assuntos
Plexo Hipogástrico/metabolismo , Pênis/inervação , Peptídeo Intestinal Vasoativo/metabolismo , Animais , Imunofluorescência , Masculino , Músculo Liso Vascular/inervação , Fibras Nervosas/metabolismo , Pênis/irrigação sanguínea , Ratos , Ratos EndogâmicosRESUMO
Retrograde dye staining, enkephalin immunocytochemistry and nerve lesion paradigms were used to determine if penile neurons in the pelvic plexus are innervated by fibers in the hypogastric nerve. In the intact major pelvic ganglion of the rat, some 80% of penile neurons are enclosed by an enkephalin-positive fiber plexus. Following surgical interruption of the pelvic nerve, 20% of penile neurons were still surrounded by an enkephalin plexus. After interruption of the pelvic nerve and the hypogastric nerve, the enkephalin plexus in the ganglion was virtually absent, including the plexus around penile neurons. Therefore, possible intrinsic sources of the enkephalin fibers such as enkephalin-positive principal neurons and small intensely fluorescent cells, do not account for the delicate enkephalin fiber system in the pelvic ganglion. It is concluded that the pelvic nerve is the major source of preganglionic innervation to penile neurons in the major pelvic ganglion. However, it is significant that the hypogastric nerve is preganglionic to about 20% of penile neurons. The pathway through the hypogastric nerve may represent an alternate vasodilator system to penile erectile tissue.
Assuntos
Gânglios Autônomos/anatomia & histologia , Plexo Hipogástrico/anatomia & histologia , Pênis/inervação , Nervos Espinhais/anatomia & histologia , Sistema Vasomotor/anatomia & histologia , Animais , Fibras Autônomas Pré-Ganglionares , Encefalinas/metabolismo , Imunofluorescência , Gânglios Autônomos/metabolismo , Masculino , Ratos , Ratos EndogâmicosRESUMO
The initial severe contralateral impairment of motor function after unilateral damage to a portion of sensorimotor (SM) cortex lessens within a few weeks after injury. In this study, two hypotheses proposed to explain recovery of behavioral function after cortical injury were tested: (1) Intact cortex adjacent to the injury reorganizes to take over the function of the destroyed area. (2) Intact SM cortex adjacent or connected to the injured area undergoes a transient shock (diaschisis), and as this dissipates, some behavioral recovery occurs. Using microstimulation of the cortex of the adult rat, movements evoked from areas near cortical injuries were studied at various times after undercut laceration, contusion, or suction ablation of an area of SM cortex. Stimulation areas were compared to those obtained from uninjured control animals and to the contralateral uninjured hemisphere. No evidence was obtained for any reorganization of stimulated motor responses in the injured hemisphere even in animals followed for as long as 475 days postinjury, suggesting other mechanisms underlying functional recovery. In intact cortex at some distance from contusion and laceration injuries, there was a marked elevation of thresholds to evoke movements that returned to normal by 9-15 days postinjury. Some intact hindlimb responses were observed after contusion injury that were absent in animals after 15 days postinjury, indicating a slow-growing lesion after this type of trauma. Surprisingly, no elevation in thresholds was noted for ablation injuries up to the edge of the cavity at any time postinjury, indicating that threshold changes near the boundary may be uncorrelated with functional recovery.
Assuntos
Mapeamento Encefálico , Córtex Cerebral/lesões , Córtex Cerebral/fisiopatologia , Animais , Estimulação Elétrica , Masculino , Ratos , Fatores de TempoRESUMO
The pelvic plexus is an association of neurons that govern visceral tissues involved in eliminative and reproductive functions. It is the singular site in the autonomic nervous system where sympathetic and parasympathetic neurons occur in the same ganglia. Within the plexus, ganglia are not randomly positioned; sympathetic neurons tend to occur more ventrally while parasympathetic neurons are located more dorsally, both in accordance with the location of their target tissues and the entry point of their corresponding preganglionic nerve tracts. For example, the vas deferens and seminal vesicle are ventral in position and thus are innervated by more ventrally located pelvic neurons. Neurochemical studies of pelvic ganglia indicate that there are some characteristic associations of putative neurotransmitters which are based on target organ distribution and in part, dictated by the variety of target tissues within each organ. Penile neurons comprise a uniform population in that they are cholinergic and also may release vasoactive intestinal polypeptide (VIP) and nitric oxide. In contrast, target tissues of the internal genitalia are more diverse, requiring adrenergic and nonadrenergic innervation and a complementary neuropeptide. Preganglionic innervation may also be coded and although sympathetic and parasympathetic fibers are cholinergic, they may differ in respect to neuropeptides and nitric oxide. Sensory neuron collaterals may also influence principal neurons as do intrinsic neurons such as small intensely fluorescent cells. Transmission through pelvic ganglia may be simple as is apparent in penile innervation, or shows a greater integrative capacity, as exemplified by the innervation of the urinary bladder. The extent of interaction of sympathetic and parasympathetic pathways at the level of the pelvic plexus remains largely unknown.
Assuntos
Plexo Hipogástrico/citologia , Animais , Humanos , Plexo Hipogástrico/química , Plexo Hipogástrico/fisiologia , NADPH Desidrogenase/metabolismo , Neuropeptídeo Y/análise , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Surgery for breast cancer continues to evolve. Less radical procedures and increasing concern about appearance and rehabilitation are now the trend. Such considerations prompted a detailed anatomic study and review of the location and course of the medial and lateral pectoral nerves, the development of a technique for immediate reconstruction of the breast during modified radical mastectomy that protects the innervation of the pectoral muscles and incorporates them in the construction of a submuscular pocket to receive a silicone breast prosthesis, and the administration of low doses of heparin sodium to prevent necrosis of ischemic breast flaps. Fifty immediate reconstructions of the breast after modified radical mastectomy were performed in 48 women with carcinoma of the breast. We believe this procedure greatly enhances rehabilitation and quality of life without diminishing the ability to diagnose or treat recurrent disease.
Assuntos
Mama/cirurgia , Mastectomia/métodos , Próteses e Implantes , Cirurgia Plástica/métodos , Adulto , Idoso , Neoplasias da Mama/cirurgia , Feminino , Humanos , Pessoa de Meia-Idade , Elastômeros de SiliconeRESUMO
Choline acetyltransferase (ChAT), a biochemical marker of cholinergic neurons, was measured in the erectile tissue of intact rats and in rats in which postganglionic fibers from the pelvic plexus were interrupted. ChAT activity in the denervated erectile tissue fell by 56% compared to control tissues. Acetylcholinesterase positive (AChE+) nerves also fell by about 48%. Penile neurons distal to the lesion probably account for the residual ChAT activity and remaining AChE+ nerve fibers in erectile tissue. These results indicate that acetylcholine is an important neurotransmitter in the regulation of penile erection.
Assuntos
Fibras Autônomas Pós-Ganglionares/enzimologia , Colina O-Acetiltransferase/metabolismo , Fibras Colinérgicas/citologia , Gânglios Parassimpáticos/enzimologia , Pênis/inervação , Animais , Fibras Autônomas Pós-Ganglionares/citologia , Fibras Colinérgicas/enzimologia , Gânglios Parassimpáticos/citologia , Masculino , Ratos , Ratos EndogâmicosRESUMO
As a part of a broader study of the reaction of the brain to injury, we report here an interesting loss of the activity of an enzyme in areas quite remote from the site of direct injury. At 36 h following a laceration or contusion injury to the hindpaw area of the motor cortex, a peculiar loss of staining for the enzyme alpha glycerophosphate dehydrogenase (alpha-GPDH) was noted. alpha-GPDH activity was markedly depressed in cortical layers II and III throughout the hemisphere on the side of the injury. The depression of alpha-GPDH activity extended far laterally across the rhinal fissure into the pyriform cortex. The decrease in alpha-GPDH staining was prominent 4 days after the injury: however, the staining pattern had returned to normal at 9 days. Enzyme changes in animals lesioned in the occipital cortex paralleled that seen in animals with a lesion in the motor cortex. Animals which had received an undercut lesion in the motor cortex 56 days earlier were contused in the occipital cortex. The old injury site presented the same sequelae of changes as seen in other lesioned animals. Additionally, a suction ablation injury involving only a small part of motor cortex resulted in the same widespread reduction of staining for alpha-GPDH in layers II and III. The derangement in energy metabolism suggests that cells in layers II and III of the cerebral cortex may be particularly vulnerable to perturbations induced by cortical trauma. These findings may be related to the diffuse and transient functional losses observed after head injury in man.
Assuntos
Concussão Encefálica/fisiopatologia , Córtex Cerebral/fisiopatologia , Depressão Alastrante da Atividade Elétrica Cortical , Glicerolfosfato Desidrogenase/metabolismo , Animais , Astrócitos/enzimologia , Córtex Cerebral/enzimologia , Córtex Cerebral/lesões , Histocitoquímica , RatosRESUMO
In order to develop some understanding of the evolution of cortical contusions, interdisciplinary studies including behavior, morphology and histochemistry were conducted at varying intervals after standardized injuries. A method for producing graded and reproducible focal cortical contusions in the rat is described. When these impact injuries are made in the "hindpaw cortical area,' specific trauma dose dependent behavioral deficits can be readily observed in the contralateral hindlimb. While most functional recovery occurs in the first two weeks after trauma, with severe contusions, deficits persist beyond 90 days. Morphologically these injuries progress from hemorrhages in white matter directly under contused cortex during the first hours after injury to the development of a necrotic cavity by 24 hours. The cavitation appears to expand over the subsequent two weeks and by 15 days is lined with fibroblast-like elements and macrophages. Intense acid phosphatase activity is seen on the borders of the area of necrosis. This lysosomal enzyme may participate in autolysis and development of focal cavitation following cortical contusion.
Assuntos
Concussão Encefálica/fisiopatologia , Córtex Cerebral/lesões , Fosfatase Ácida/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Membro Posterior/inervação , Histocitoquímica , Métodos , Necrose , Postura , RatosRESUMO
The main penile or cavernous nerve is usually regarded as the most important vasodilator projection in the rat. Although other descending pathways have been described, there is little detailed information on their importance. In this present report, we provide topographic and quantitative information on lateral and ventral penile branches and examine the vasodilator fibers which join the pudendal neurovascular bundle. Seventeen Sprague-Dawley rats were used. The techniques included injection of dye in the penis to label neurons in the pelvic plexus in combination with transection of the main penile nerve (MPN). NADPH diaphorase (NADPH-d) histochemistry was used to assess the effects of transection of vasodilator pathways on innervation of the penis and for in situ staining of the pelvic plexus. Distinct clusters of penile neurons are aggregated at the origin of several nerve tracts leaving the posterior margin of the major pelvic ganglion (MPG). Multiple NADPH-d+ fiber bundles coursed over the anterior surface of the prostate to reach the penis. Branches from these tracts joined the pudendal neurovascular bundle proximal to the hilum of the penis and provided innervation to the artery throughout its course in the pudendal canal. Consistent with the presence of multiple penile pathways, transection of the MPN reduced, but did not eliminate retrograde labeling of penile neurons in the MPG and only modestly decreased NADPH-d+ fibers in the penis. This study confirms that there are multiple pathways by which vasodilator fibers reach the penis. If a similar allocation of vasodilator output is present in man, preservation of finer branches of the pelvic plexus would be important in surgical procedures on the prostate.
Assuntos
Vias Neurais , Pênis/inervação , Vasodilatação , Animais , Artérias/inervação , Denervação , Histocitoquímica , Masculino , NADPH Desidrogenase/análise , Fibras Nervosas/enzimologia , Fibras Nervosas/ultraestrutura , Pênis/irrigação sanguínea , Ratos , Ratos Sprague-DawleyRESUMO
NADPH diaphorase histochemistry was used to determine whether the rat anoocccygeus (AC) and retractor penis (RP) muscles are innervated by nerves capable of synthesizing nitric oxide. In both tissues, muscle fascicles were enclosed by a varicose plexus of NADPH diaphorase positive (ND+) fibers. Perikarya of neurons on the surface of the AC muscle were also intensely stained for NADPH diaphorase. Many AC-RP ganglion cells in the pelvic plexus, located by the retrograde tracer Fluorogold, also stained for the enzyme. However, a significant population of AC-RP neurons in this location remained unstained. These results provide further evidence that nitric oxide may be an important neurotransmitter in these tissues.
Assuntos
Músculos/inervação , NADPH Desidrogenase/metabolismo , Pênis/inervação , Estilbamidinas , Animais , Ácido Ditionitrobenzoico , Corantes Fluorescentes , Gânglios Parassimpáticos/citologia , Gânglios Parassimpáticos/enzimologia , Histocitoquímica , Masculino , Músculos/enzimologia , NADPH Desidrogenase/imunologia , Neurônios/enzimologia , Sistema Nervoso Parassimpático/enzimologia , Sistema Nervoso Parassimpático/imunologia , Pênis/enzimologia , Ratos , Ratos Sprague-DawleyRESUMO
The presence of adrenergic innervation was investigated in four different vascular segments of the neotenic tiger salamander, Ambystoma tigrinum, by histofluorescent staining for catecholamines. The segments were the respiratory section of the gill, the branchial shunt vessels, a vascular plexus in the pulmonary artery, and the dorsal aorta. No adrenergic fibers were detected in the respiratory section of the gill or the pulmonary arterial plexus. In contrast, the branchial shunt vessels contained both adrenergic varicosities and catecholamine-containing cell bodies. These cells resemble Type I cells of the mammalian carotid body and amphibian carotid labyrinth. Adrenergic innervation of the dorsal aorta was sparse and restricted to the adventitia. The results suggest that adrenergic nerves may directly regulate blood flow in the gill, and thus gas exchange, by controlling vascular resistance of the branchial shunts. The contractile state of the dorsal aorta may also be under adrenergic control. In addition, it is suggested that the adrenergic cells of the branchial shunts may serve a receptor function in being sensitive to arterial blood gases.
Assuntos
Fibras Adrenérgicas/análise , Aorta/inervação , Brânquias/inervação , Artéria Pulmonar/inervação , Fibras Adrenérgicas/fisiologia , Ambystoma , Animais , Aorta/análise , Brânquias/análise , Histocitoquímica , Artéria Pulmonar/análiseAssuntos
Gânglios Autônomos/citologia , Receptores Adrenérgicos/isolamento & purificação , Fibras Adrenérgicas/ultraestrutura , Animais , Grânulos Citoplasmáticos/ultraestrutura , Hidroxidopaminas/farmacologia , Interneurônios/ultraestrutura , Microscopia de Fluorescência , Coelhos , Membranas Sinápticas/ultraestrutura , Vesículas Sinápticas/ultraestruturaRESUMO
Although a number of morphological studies have investigated the vascular system of the rat kidney, minimal data are available on the detailed anatomy of the efferent arterioles located throughout the cortex of the kidney. In the present study, the renal vascular system was filled with Microfil and the various efferent arteriole patterns were examined extensively. The efferent vessels of the entire cortex appear to form three major patterns which in turn divided the cortex into three separate regions: the outer, middle and inner cortex. The efferent arterioles of the outer cortex leave the glomerulus and run perpendicular to the kidney capsule. However, as the efferent arterioles ascend, they may show three variations in the way they branch: (1a) the efferent arteriole does not branch until directly beneath the capsule, (1b) the efferent vessel begins to divide into its major branches 100-200 mum below the surface of the kidney and (1c) the efferent vessel has only a short course before giving off many side branches. In the middle cortical area, the branches of the efferent arteriole run lateral to the glomerulus. However, the efferent arterioles of the inner cortex have a few branches which run lateral to the glomerulus while most of them descend into the medulla as vasa rectae. The unique morphological features of the efferent arterioles of the outer cortex are of particular interest in light of the functional data which suggests that the reabsorption of fluid by peritubular capillaries may indeed regulate the rate of net tubular sodium reabsorption.
Assuntos
Córtex Renal/irrigação sanguínea , Glomérulos Renais/irrigação sanguínea , Animais , Artérias/anatomia & histologia , Masculino , RatosRESUMO
Target organ responses to sympathetic nerve stimulation are altered following partial decentralization of the pelvic plexus in the rat. One possible explanation for the new responses is that nerve injury has led to a reorganization of synaptic connections within pelvic ganglia. Since one measure of synaptic influence is the occurrence of a pericellular plexus of varicose fibers around autonomic ganglion cells, the present study has used immunocytochemistry for enkephalin (ENK), a peptide present in nerve fibers in the pelvic plexus, to follow changes in the innervation of penile ganglionic neurons after interruption of preganglionic pathways. Penile ganglion cells were located by the injection of the tracer Fluorogold into the penile crura. Four days after lesion of the pelvic nerve, innervation of penile neurons falls from 76% to 20%. This number increases however, to 31% in chronically (6 weeks) lesioned animals. In the totally decentralized ganglia, ENK immunoreactive (IR) fibers enclose fewer than 12% of the penile neurons 4 days after nerve lesion. However, this value rises to 35% in the chronically decentralized pelvic ganglion. Therefore, recovery of an enkephalin plexus occurs irrespective of whether the pelvic nerve, or both the hypogastric and pelvic nerve have been cut. Although these findings suggest sprouting within partially decentralized ganglia, the similar incidence of an ENK plexus in ganglia subjected to chronic partial or total decentralization indicates that preganglionic fibers are not responsible for the emergent fibers.
Assuntos
Denervação Autônoma , Encefalinas/metabolismo , Gânglios Autônomos/metabolismo , Neurônios/metabolismo , Pênis/inervação , Estilbamidinas , Animais , Fibras Autônomas Pré-Ganglionares/imunologia , Fibras Autônomas Pré-Ganglionares/metabolismo , Encefalinas/imunologia , Corantes Fluorescentes , Gânglios Autônomos/citologia , Gânglios Autônomos/imunologia , Imuno-Histoquímica , Masculino , Plasticidade Neuronal/fisiologia , Neurônios/imunologia , Ratos , Ratos Sprague-DawleyRESUMO
Surgical interruption of the pelvic nerve elevated immunoreactive vasoactive intestinal polypeptide in the major pelvic ganglion of the rat. Two changes were noted: (i) varicose and smooth fibers appeared in the neuropil and (ii) a small number of ganglion cells became highly reactive for the polypeptide. A more proximal transection of preganglionic parasympathetic fibers, at their origin from spinal nerves, had no effect on vasoactive intestinal polypeptide immunoreactivity. Ganglion cells were labeled when a dye was applied to the cut distal end of the pelvic nerve. We conclude that a population of vasoactive intestinal polypeptide-containing neurons in the major pelvic ganglion send their axons proximally in the pelvic nerve.
Assuntos
Pelve/inervação , Peptídeo Intestinal Vasoativo/análise , Animais , Masculino , Ratos , Ratos EndogâmicosRESUMO
The ischiourethralis (IU), a striated perineal muscle presumed to be involved in sexual reflexes, was studied in the rat. The paired muscle arises from the penile crus and the penile bulb and unites in a raphe over the deep dorsal vein of the penis. Retrograde tracing studies show that the muscle is innervated by neurons in the dorsolateral nucleus of the lumbar spinal cord, a pudendal nerve motor nucleus which also innervates the ischiocavernosus muscle. Excision of the IU muscle did not interfere with the ability of males to display normal copulatory behavior, nor did it affect significantly the number and intensity of reflexive erections. It nevertheless remains possible that the IU may contribute to intense glans erection by compressing the deep dorsal vein.
Assuntos
Músculos/anatomia & histologia , Pênis/anatomia & histologia , Animais , Masculino , Músculos/inervação , Músculos/fisiologia , Ereção Peniana/fisiologia , Pênis/inervação , Pênis/fisiologia , Ratos , Ratos EndogâmicosRESUMO
To determine the reaction of adrenergic ganglion cells and small intensely fluorescent (SIF) cells to chronic deafferentation, catecholamine fluorescence of the major pelvic ganglion (MPG) of the rat has been studied following section of the hypogastric nerve, pelvic nerve and sympathetic trunk. Only minor changes occurred following section of the hypogastric nerve; the fluorescence surrounding a few adrenergic ganglion cells became brighter. In contrast, pelvic neurectomy resulted in the appearance of numerous varicose fibres and an increase in the fluorescent intensity of fibres enclosing many ganglion cells. Varicose fibres seem to originate from adrenergic ganglion cells and SIF cells. In many instances, nests of SIF cells gave rise to radially oriented fibres. Removal of the sympathetic trunk appeared to have no effect on the MPG. It is suggested that the appearance of varicose fibres from SIF cells following deafferentation may be due to collateral sprouting of these cells or to the increased fluorescence of pre-existing processes.
Assuntos
Fibras Adrenérgicas/metabolismo , Gânglios Autônomos/metabolismo , Pelve/inervação , Fibras Adrenérgicas/citologia , Vias Aferentes/metabolismo , Animais , Fluorescência , Gânglios Autônomos/citologia , Plexo Hipogástrico/metabolismo , Masculino , Ratos , SimpatectomiaRESUMO
Highly significant (P smaller than 0.0025) increases in adenylate cyclase activity were seen at all fetal age periods (5-17 weeks) whenever sodium fluoride (5-10 mM) was added to the enzyme prepared from human myocardium. Norepinephrine (NE) at 10-4 M significantly elevated adenylate cyclase activity commencing at 6-7 weeks (P smaller than 0.01). Beginning at 8-9 fetal weeks, glucagon (6x10-6 M) effectively activated adenylate cyclase. Other hormonal agents, namely, histamine, epinephrine, and isoproterenol at 10-4 M, demonstrated an ability to activate the enzyme (P smaller than 0.025) by as early as 6-7 weeks and continued to act in this manner throughout the remainder of the developmental periods investigated. The beta blocking agents, propranolol, significantly inhibited (P smaller than 0.25) the stimulation of adenylate cyclase by NE throughout the 8-15 fetal week periods.
Assuntos
Adenilil Ciclases/metabolismo , Coração Fetal/enzimologia , Ativação Enzimática/efeitos dos fármacos , Epinefrina/farmacologia , Feminino , Fluoretos/farmacologia , Idade Gestacional , Glucagon/farmacologia , Histamina/farmacologia , Humanos , Isoproterenol/farmacologia , Norepinefrina/antagonistas & inibidores , Norepinefrina/farmacologia , Tamanho do Órgão , Fentolamina/farmacologia , Gravidez , Propranolol/farmacologiaRESUMO
Substance P immunoreactivity in the major pelvic ganglion (MPG) of the rat was studied to define a possible role for this neuropeptide in functions of the pelvic portion of the autonomic nervous system. Substance P immunoreactivity was found in three locations in the ganglion: 1) as a plexus of varicose fibers, 2) in small intensely fluorescent (SIF) cells, and 3) after colchicine pretreatment, in some principal neurons. The perineuronal plexus of fibers appeared as small varicosities closely related to the somae of principal neurons. Approximately 10-20% of principal neurons were enclosed by a substance P-positive plexus. SIF cells were intensely stained for substance P. The general relationships of SIF cells in this ganglion were confirmed by their staining for substance P: their occurrence singly or in large clusters, their short tapering processes often related to principal neurons, and the occasional presence of a beaded process. Colchicine treatment resulted in the appearance of rare principal neurons that stained for substance P. The pelvic nerve was surgically interrupted to determine whether the perineuronal plexus of varicose fibers had an intrinsic origin or arose from cell bodies outside the ganglion. The perineuronal plexus was virtually absent following this procedure. The results of this study indicate that principal neurons in the major pelvic ganglion may be subject to the influence of substance P derived from two sources: 1) intrinsic substance P-containing SIF cells and 2) neurons probably residing in dorsal root ganglia. The nature of principal neurons that acquire staining for substance P after colchicine is unclear.
Assuntos
Gânglios Autônomos/imunologia , Pelve/inervação , Substância P/imunologia , Animais , Colchicina/farmacologia , Histocitoquímica , Imunoquímica , Ratos , Ratos EndogâmicosRESUMO
As a basis for understanding the mechanism of erection in an animal model frequently used in research in reproductive biology, the angioarchitecture of the penis of the rat has been described using scanning electron microscopy. Study of the penile vasculature of the rat indicates that the corpora cavernosa penis and the corpus spongiosum are independent erectile tissues, each with its own arterial and venous vessels. The large vascular spaces and abundant smooth muscle of the penile crura are compatible with its role in regulating blood flow to more distal penile tissues. Helicine arteries of the crura, but not the parent deep penile artery or arteries elsewhere, have muscular cushions in their walls. The venous drainage of the penile crura is via subtunical veins which are thought to be compressed during erection to elevate pressure within the penis. Large, paired cavernous veins drain the shaft of the penis. A unique method for inhibiting blood flow from the penis is indicated by the division of the cavernous veins into smaller channels prior to joining the subtunical venous plexus. Erectile tissue in the bifid origins of the corpus spongiosum has abundant cavernous muscle, while in the remainder of the corpus spongiosum little smooth muscle lines the cavernous spaces. The cavernous spaces on either side of the urethra coalesce to form vessels, each of which communicates with cavernous spaces in the glans. In addition, a bypass of the glans is effected by communication of these vessels directly with the deep dorsal vein. The apparent absence of muscular pads in vessels of the spongiosum, the relative paucity of cavernous smooth muscle, and the ample venous drainage provided by the deep dorsal vein may account for the lack of a venous occlusive mechanism similar to that of the corpora cavernosa penis.