Ontogeny of calcitonin gene‐related peptide immunoreactivity in rat lumbar motoneurons: Delayed appearance and sexual dimorphism in the spinal nucleus of the bulbocavernosus

Forger, N.G.; Ll, Hodges; Breedlove, S. Marc

doi:10.1002/cne.903300407

Cited by 8 publications

(1 citation statement)

References 37 publications

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“…Specifically, females can be induced to retain masculine numbers of DLN neurons by treatment during the prenatal period with dihydrotestosterone, an androgenic metabolite of testosterone; however, both prenatal and postnatal treatments are required for a similar effect in the SNB (Breedlove & Arnold, 1983b;Breedlove et al, 1982;Goldstein & Sengelaub, 1990Sachs & Thomas, 1985;. Furthermore, SNB motor neurons exhibit a very late maturity, relative to both DLN and RDLN neurons, in expressing calcitonin gene-related peptide, a molecule that plays a role in neuromuscular interaction (Forger, Hodges, & Breedlove, 1993).…”

Section: Discussionmentioning

confidence: 99%

Number, size, and regional distribution of motor neurons in the dorsolateral and retrodorsolateral nuclei as a function of sex and neonatal stimulation

1996

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Motor neurons were measured in the retrodorsolateral nucleus (RDLN) and the dorsolateral nucleus (DLN) of adult male and female rats that were reared with normal or reduced levels of maternal anogenital stimulation. In contrast with findings for the spinal nucleus of the bulbocavernosus, which is located in the same spinal segments, reduced stimulation had no effect on neuron number in either nucleus. However, several regional and sex differences were observed. Rostrally located neurons were larger in both the RDLN and the DLN; these location effects were greater in females. There was no sex difference in RDLN neuron size, but DLN neurons were larger in females, particularly in the rostral region. Females had significantly more cells in the RDLN, a nucleus previously considered nondimorphic, whereas males had more DLN neurons. Both regional and sex differences may reflect local differences in trophic factors from targets or afferents. © 1996 John Wiley & Sons, Inc.

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Section: Discussionmentioning

confidence: 99%

Number, size, and regional distribution of motor neurons in the dorsolateral and retrodorsolateral nuclei as a function of sex and neonatal stimulation

1996

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Calcitonin gene-related peptide-like immunoreactivity in motoneuron pools innervating different hind limb muscles in the rat

et al. 1993

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The content of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) in motoneurons was studied in four motor pools supplying muscles in the rat hind limb subserving different types of motor activity. The motor pools were identified by retrograde labeling with horseradish peroxidase or fluorophore-conjugated dextran amines, which were injected into the soleus, tibialis anterior, lateral gastrocnemius, or abductor digiti minimi muscles. After processing for immunohistochemistry, a semiquantitative evaluation was carried out to estimate the proportion of strongly, intermediately, and weakly labeled motoneurons, as well as motoneurons totally lacking CGRP staining. This revealed a considerable diversity in the intensity of CGRP labeling even for motoneurons in the same motoneuron pool. Thus, strongly labeled cells, as well as cells devoid of CGRP label, were found in all four motoneuron pools. However, a difference was found in the distribution of motoneurons innervating muscles with a dominant composition of fast and slow motor units, respectively, in that a larger fraction of the latter type lacked CGRP-LI. Moreover, generally motoneurons in the small motor units of the abductor digiti minimi muscle displayed weaker staining, and a larger proportion of cells was totally devoid of CGRP-LI (16%) compared with larger motor units of the other three muscles (1-10%). Small-sized cells within the gamma-motoneuron size range were weakly stained or, more frequently, totally devoid of CGRP label (50%) as compared to larger cells, presumably representing alpha-motoneurons (1-16%). Five days after axotomy all four studied motoneuron pools displayed stronger CGRP labeling than corresponding unlesioned pools. However, a considerable variation in CGRP labeling persisted also among axotomized motoneurons. These results indicate that motoneurons normally display a great variation in CGRP-LI levels, but that motoneurons of small and slow-twitch motor units in general have lower levels than motoneurons of large and fast-twitch motor units, respectively. After axotomy, CGRP-LI increases in lesioned motoneuron pools compared with normal, but in a fraction of the axotomized motoneurons the increase seems to be discrete or even absent. The possible physiological implications of these findings are discussed.

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Spinal control of penile erection

1997

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Smooth muscle relaxation of penile arteries, the corpus cavernosum, and the corpus spongiosum, leading to penile erection, results from parasympathetic neural pathway activation and, likely, simultaneous inhibition of sympathetic outflow. Proerectile parasympathetic outflow is reflexively activated by sensory information of peripheral origin, conveyed by the dorsal penile nerve, and reflexive erections are supported by an intraspinal circuitry. Supraspinal influences modulate the reflex. Information integrated at or originating from supraspinal structures may also elicit penile erection. Several neurotransmitters are involved in either the modulation of the spinal reflex or the mediation of supraspinal influences. Spinal cord injury differently alters reflexive penile erection or erection from a central origin, depending on the neurologic level of injury.

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Ontogeny of calcitonin gene‐related peptide immunoreactivity in rat lumbar motoneurons: Delayed appearance and sexual dimorphism in the spinal nucleus of the bulbocavernosus

Cited by 8 publications

References 37 publications

Number, size, and regional distribution of motor neurons in the dorsolateral and retrodorsolateral nuclei as a function of sex and neonatal stimulation

Number, size, and regional distribution of motor neurons in the dorsolateral and retrodorsolateral nuclei as a function of sex and neonatal stimulation

Calcitonin gene-related peptide-like immunoreactivity in motoneuron pools innervating different hind limb muscles in the rat

Spinal control of penile erection

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