Striated Perineal Muscles: Location of Autonomic, Sensory, and Somatic Neurons Projecting to the Male Pig Bulbospongiosus Muscle

Gazza

et al. 2012

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Aim of the present study was to verify, by means of double retrograde neuronal tracers technique, the hypothesis that a subpopulation of sensory and autonomic neurons send collateral axons to both smooth and striated genital muscles. We also wanted to define the neurochemical content of the eventually retrogradelly double labeled (RDL) neurons in the sympathetic trunk ganglia (STG). We used six intact pigs and we injected the tracer Diamidino Yellow (DY) in the smooth left retractor penis muscle (RPM) and the tracer Fast Blue (FB) in the striated left bulbospongiosus muscle (BSM). Rare (2 6 0.6) RDL neurons were found in the ipsilateral S2 spinal ganglion (SG), 220 6 42 in the ipsilateral STGs, from L3 to S3, 19 6 15 in the contralateral S1-S2 ones and 22 6 5 in the bilateral caudal mesenteric ganglia (CMG). The RDL neurons of the STG were IR for TH (85 6 13%), DbH (69 6 17%), NPY (69 6 23%), nNOS (60 6 11%), LENK (54 6 19%), VIP (53626%), SOM (40 6 8%), CGRP (34 6 12%), SP (31 6 16%), and VAChT (28 6 3%). Our research highlights the presence of sensory and sympathetic neurons with qualitatively different neurochemical content sending axons both to the smooth RPM and to the striated BSM of the pig. These RDL neurons are likely to project to the smooth vasal musculature to create the ideal physiological conditions in which these muscles can optimize the erectile function.

“…The location and number corresponded to the results obtained in our previous studies Botti et al, 2009). …”

Section: Distribution Of Double-labeled Neuronssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 88%

“…Data about the localization and number of the neurons projecting only to the RPM or only to the BSM have already been pubblished Botti et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

Section: Vacht-immunoreactivitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Sensory and Autonomic Neurons Project Both to the Smooth Retractor Penis and to the Striated Bulbospongiosus Muscles. Neurochemical Features of the Sympathetic Subset

Gazza

et al. 2012

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Neurochemical Features of the Autonomic Neurons Projecting to the Cremaster Muscle of the Boar

Cacchioli

et al. 2015

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The cremaster muscle (CM) is a striated muscle showing some unusual features for ordinary striated muscles, in fact it receives, besides somatic innervation, a conspicuous autonomic sympathetic innervation. The autonomic neurons associated with the CM of 4 male intact pigs were typified combining the retrograde nontrans-synaptic fluorescent tracer Fast Blue (FB) and double labeling immunohistochemical methods. We collected the L4 sympathetic trunk ganglion (STG), that our preliminary studies proved to contain the highest number (575.5 6 152.93; mean-6 S.E.M., n 5 4) of FB1 sympathetic neurons projecting to CM. About half of the CM projecting neurons of this ganglion were catecholaminergic and showed the colocalization of Tyrosine Hydroxylase (TH) with Neuropeptide Y (NPY), Leu-Enkephaline (LENK), Vasoactive Intestinal Polypeptide (VIP), Calcitonine Gene Related Peptide (CGRP), Substance P (SP), neuronal Nitric Oxyde Sinthase (n-NOS), and Vesicular Acetylcholine Transporter (VAChT). The noncatecholaminergic neurons were immunoreactive for all the other markers tested, even if in small percentages. The conspicuous and heterogeneous contribution of the sympathetic autonomic neurons to the muscle innervation is consistent with the hypothesis of a possible origin of the CM fibers by transdifferentiation of the smooth muscle-like gubernaculum mesenchyma into striated myotubes, suggesting that the cremaster myogenesis is independent from that of the abdominal muscles.

Immunohistochemical Properties of the Peripheral Neurons Projecting to the Pig Bulbospongiosus Muscle

Cacchioli

et al. 2016

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Retrograde neuronal tracing and single labelling immunofluorescence methods were used to define the neurochemical content of the peripheral autonomic and sensitive neurons projecting to the male pig striated bulbospongiosus muscle (BSM). The retrograde fluorescent neuronal tracer Fast Blue (FB) was injected into the left bulbospongiosus muscle of four intact impuberal pigs. After a 10-day survival time, the ipsilateral sacral sympathetic trunk ganglia (STGs), the caudal mesenteric ganglion (CMG), and the sacral spinal ganglia (SGs) were collected from each animal. In FB1 neurons of these ganglia, the presence of cathecolamine-(tyrosine hydroxylase-TH), acetylcholine-(vesicular acetylcholine transporter-VChAT), or nitric oxide-synthesizing (neuronal Nitric Oxide Synthase-nNOS) enzymes and of some biologically active peptides (calcitonine gene-related peptide-CGRP, Leu-Enkephaline-LENK, Neuropeptide Y-NPY, Substance P-SP and Vasoactive Intestinal Peptide-VIP) were studied. The ipsilateral STGs FB1 neurons showed immunoreactivity principally for TH and NPY and in decreasing order for VIP, VChAT, SP, CGRP, nNOS, and LENK. The left CMG FB1 neurons were immunoreactive to TH and NPY, and in smaller proportions for VIP, LENK, VChAT, CGRP, nNOS, and SP. The ipsilateral SGs FB1 neurons resulted immunoractive for CGRP, LENK, NPY, nNOS, SP, and VChAT. The heterogeneous neurochemical content of the peripheral neurons projecting to the pig BSM allows us to hypothesize the involvement of autonomic ganglia in the activity of both blood vessels and striated fibers of the muscle and the involvement of sensory ganglia in the afferent transmission from the muscle to spinal cord and in antidromic mechanisms that causes the relaxation of the BSM blood vessels. Anat Rec, 299:1192Rec, 299: -1202Rec, 299: , 2016. V C 2016 Wiley Periodicals, Inc.Key words: immunohistochemistry; retrograde tracing; peripheral neurons; bulbospongiosus muscle; pigThe striated and paired bulbospongiosus muscle (BSM) is a perineal muscle associated to the genital organs. It is a single muscle in male mammals, while in females it is divided in vestibule and vulva constrictor muscles. In the male, it originates laterally from the tunica albuginea of the penis corpora spongiosa and terminates on the perineum median septum (Schaller, 1992).