NeuroanatomyGalanin and neurokinin-1 receptor immunoreactivity spinal neurons controlling the prostate and the bulbospongiosus muscle identified by transsynaptic labeling in the rat
Section snippets
Animals
Adult Sprague–Dawley male rats, body weight 250–330g (Harlan France, Gannat, France) were used for the experiments. Rats were kept in animal facilities under a 12-h light/dark cycle, light at 8:00 a.m., with food and water ad libitum. Twenty-two rats have received PRV injections into the BS muscle, and in 18 rats PRV injections were performed into the right ventral prostatic lobe. After PRV injections, rats were housed one per cage and observed daily. Rats were allowed to survive for 3 days (n
PRV spinal cord labeling following injection into the BS muscle
Three days after PRV injection, labeled neurons were only found in the ipsilateral dorsomedial nucleus (DM) located in the VH of the L5–L6 spinal segment (not shown). Labeled cells, presumably motoneurons innervating the right BS muscle, were large with long dendrites projecting ventrolaterally, medially and dorsally. Among five animals injected with PRV and killed after 3 days, only one animal displayed a single labeled neuron in the DGC at the L3 level.
After a survival period of 4 days,
Discussion
The BS muscle and the prostate are key pelvic–perineal anatomical structures involved in the ejaculation process respectively in the emission and the expulsion phases. We first describe in detail in the lumbar spinal cord the distribution of neurons which are retrogradely labeled by PRV after injection in these peripheric organs, and then demonstrate their relationship with spinal GAL and NK1-R neurons.
Several studies have previously described the neural pathways from the spinal cord to BS
Conclusion
We have identified a group of lumbar spinal neurons which expressed GAL or to a lesser extent NK1-R, located in lamina X of L3 and L4 levels which were in close connection with DM motoneurons innervating the BS muscle and both parasympathetic and sympathetic preganglionic neurons destined to the prostate. These data provide further anatomical evidence for a crucial role for LSt cells in coordinating the spinal control of ejaculation.
Acknowledgments
Pr. Lynn W. Enquist (Department of Molecular Biology, Princeton University, Princeton, NJ, USA) is warmly acknowledged for his contribution by providing the bartha strain of PRV and the antiserum against PRV.
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2015, Handbook of Clinical NeurologyCitation Excerpt :A key element of the SGE is composed of neurons (lumbar spinothalamic neurons: LSt) that reside around the central canal in laminae X and VII (medial part) of the L3–4 spinal segments (Truitt and Coolen, 2002). Lumbar spinothalamic neurons project to sympathetic and parasympathetic preganglionic neurons innervating the prostate and seminal vesicles (Xu et al., 2005; Sun et al., 2009). Moreover, connections between LSt and motoneurons innervating the BS muscle have been reported (Xu et al., 2005).
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2014, Journal of Sexual MedicineCitation Excerpt :Interestingly, sexual behavior (intromission, ejaculations, and penile reflexes) in male rats has been shown to appear around day 49 which matches the neuroanatomical changes seen in the DMN motoneurons [43,44]. Several studies have documented a group of neurons in the lumbar spinal cord that exhibit sexual dimorphism in rats; this population of neurons expresses galanin, cholecystokinin, enkephalin and NK1 receptors [45-49]. These neurons are located within the third and fourth lumbar segments of the spinal cord in the medial gray (lamina X and medial lamina VII) and project to the thalamic region of the brain [45,46].
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2011, Journal of Sexual MedicineCitation Excerpt :There are several evidences about the implication of medial preoptic area, hypothalamic paraventricular nucleus, periaqueductal gray, nucleus paragigantocellularis, and other nuclei in the brain for central modulation of ejaculation [6,7]. Spinal ejaculatory generator that is known as another important center in the control of ejaculation has been identified in lamina VII and X in the lumbar spinal segments (L3–L4) of rats [6-10]. Despite this knowledge, the exact mechanism and affected level of the nervous system in hyperthyroidism‐induced PE is not yet known.