Sex difference in Onuf's nucleus homologue in the Asian musk shrew

Polak, Kathryn; Freeman, Louise M.

doi:10.1016/j.brainres.2010.05.056

Cited by 6 publications

(6 citation statements)

References 26 publications

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“…We also found a sex difference in ON motoneuron number in Damaraland mole-rats consistent with all other mammalian species studied [e.g. Breedlove and Arnold, 1980;Breedlove, 1986, 1987;Ulibarri et al, 1995;Polak and Freeman, 2010], with the exception of the naked mole-rat [Peroulakis et al, 2002;Seney et al, 2006]. Thus, the current findings demonstrate that sex can influence neural morphology in a eusocial mammal.…”

Section: Discussionsupporting

confidence: 64%

Social Status and Sex Effects on Neural Morphology in Damaraland Mole-Rats, <i>Fukomys damarensis</i>

et al. 2011

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We previously reported that in a eusocial rodent, the naked mole-rat (Heterocephalus glaber), traditional neural sex differences were absent; instead, neural dimorphisms were associated with breeding status. Here we examined the same neural regions previously studied in naked mole-rats in a second eusocial species, the Damaraland mole-rat (Fukomys damarensis). Damaraland mole-rats live in social groups with breeding restricted to a small number of animals. However, colony sizes are much smaller in Damaraland mole-rats than in naked mole-rats and there is consequently less reproductive skew. In this sense, Damaraland mole-rats may be considered intermediate in social organization between naked mole-rats and more traditional laboratory rodents. We report that, as in naked mole-rats, breeding Damaraland mole-rats have larger volumes of the principal nucleus of the bed nucleus of the stria terminalis and paraventricular nucleus of the hypothalamus than do subordinates, with no effect of sex on these measures. Thus, these structures may play special roles in breeders of eusocial species. However, in contrast to what was seen in naked mole-rats, we also found sex differences in Damaraland mole-rats: volume of the medial amygdala and motoneuron number in Onuf’s nucleus were both greater in males than in females, with no significant effect of breeding status. Thus, both sex and breeding status influence neural morphology in Damaraland mole-rats. These findings are in accord with the observed sex differences in body weight and genitalia in Damaraland but not naked mole-rats. We hypothesize that the increased sexual dimorphism in Damaraland mole-rats relative to naked mole-rats is related to reduced reproductive skew.

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Section: Discussionsupporting

confidence: 64%

Social Status and Sex Effects on Neural Morphology in Damaraland Mole-Rats, <i>Fukomys damarensis</i>

et al. 2011

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“…In all five subjects the tracer was confined within the smooth musculature of the UBT. To verify whether there was tracer spreading into the urethral sphincter muscle, we also analyzed transverse sections of the last lumbar (L7) and the first three sacral (S1–S3) spinal cord segments, which could contain pudendal efferent neurons (often clustered in Onuf's nucleus) innervating the perineal muscle correlated to micturition, defecation, and copulation, as demonstrated in several species such as humans (Onufrowicz,1889; Pullen et al,1997), monkeys (Ueyama et al,1985; Roppolo et al,1985), dogs and cats (Kuzuhara et al,1980; Ueyama et al,1984), and murine species (McKenna and Nadelhaft,1986; Polak and Freeman,2010).…”

Section: Resultsmentioning

confidence: 93%

Neurochemical features of boar lumbosacral dorsal root ganglion neurons and characterization of sensory neurons innervating the urinary bladder trigone

Russo

Clavenzani

Sorteni

et al. 2012

J of Comparative Neurology

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Porcine lumbosacral dorsal root ganglion (DRG) neurons were neurochemically characterized by using six neuronal markers: calcitonin gene‐related peptide (CGRP), substance P (SP), neuronal nitric oxide synthase (nNOS), neurofilament 200kDa (NF200), transient receptor potential vanilloid 1 (TRPV1), and isolectin B4 (IB4) from Griffonia simplicifolia. In addition, the phenotype and cross‐sectional area of DRG neurons innervating the urinary bladder trigone (UBT) were evaluated by coupling retrograde tracer technique and immunohistochemistry. Lumbar and sacral DRG neuronal subpopulations were immunoreactive (IR) for CGRP (30 ± 3% and 29 ± 3%, respectively), SP (26 ± 8% and 27 ± 12%, respectively), nNOS (21 ± 4% and 26 ± 7%, respectively), NF200 (75 ± 14% and 81 ± 7%, respectively), and TRPV1 (48 ± 13% and 43 ± 6%, respectively), and labeled for IB4 (56 ± 6% and 43 ± 10%, respectively). UBT sensory neurons, which were distributed from L2 to Ca1 DRG, had a segmental localization, showing their highest density in L4–L5 and S2–S4 DRG. Lumbar and sacral UBT sensory neurons expressed similar percentages of NF200 immunoreactivity (64 ± 33% and 58 ± 12%, respectively) but showed a significantly different immunoreactivity for CGRP, SP, nNOS, and TRPV1 (56 ± 9%, 39 ± 15%, 17 ± 13%, 62 ± 10% vs. 16 ± 6%, 16 ± 11%, 6 ± 1%, 45 ± 24%, respectively). Lumbar and sacral UBT sensory neurons also showed different IB4 labeling (67 ± 19% and 48 ± 16, respectively). Taken together, these data indicate that the lumbar and sacral pathways probably play different roles in sensory transmission from the UBT. The findings related to cell size also reinforced this hypothesis, because lumbar UBT sensory neurons were significantly larger than sacral ones (1,112 ± 624 μm2 vs. 716 ± 421 μm2). J. Comp. Neurol. 521:342–366, 2013. © 2012 Wiley Periodicals, Inc.

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“…The magnitude of the sex difference in motoneuron number found here is larger than that in humans (25% more motoneurons in ventrolateral Onuf’s nucleus of men; Forger and Breedlove, 1986), and similar to that in Japanese monkeys (~50%; Ueyama et al, 1985). Thus, Onuf’s nucleus motoneuron number is sexually differentiated in primates, as it is in several rodent species, at least two carnivorans, and one insectivore (Breedlove and Arnold, 1980; Forger and Breedlove, 1986, 1987a; Forger et al, 1996; Holmes et al, 2009; Polak and Freeman, 2010; Ulibarri et al, 1995; Wee and Clemens, 1987). As expected, we found no difference between control males and females in the number of motoneurons in Pes9, a cell group that innervates foot muscles.…”

Section: Discussionmentioning

confidence: 99%

Effects of sex and prenatal androgen manipulations on Onuf's nucleus of rhesus macaques

Forger

Ruszkowski

Jacobs

et al. 2018

Hormones and Behavior

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The role of gonadal steroids in sexual differentiation of the central nervous system (CNS) is well established in rodents, but no study to date has manipulated androgens prenatally and examined their effects on any CNS structure in a primate. Onuf's nucleus is a column of motoneurons in the sacral spinal cord that innervates the striated perineal muscles. This cell group is larger in males than in females of many species, due to androgens acting during a sensitive perinatal period. Here, we examined Onuf's nucleus in 21 adult rhesus monkeys, including control males and females, as well as males whose mothers had been treated with an anti-androgen or testosterone during gestation. We found a robust sex difference, with more motoneurons in control males than in females. The soma size of Onuf's nucleus motoneurons was also marginally larger in males. Treatment with the anti-androgen flutamide for 35-40 days during early gestation partially blocked masculinization of Onuf's nucleus: motoneuron number in flutamide-treated males was decreased relative to control and testosterone-treated males, but remained greater than in females, with no effect on cell size. A control motor nucleus that innervates foot muscles (Pes9) showed no difference in motoneuron number or size between control males and females. Prenatal testosterone treatment of males did not alter Onuf's nucleus motoneuron number, but did increase the size of both Onuf's and Pes9 motoneurons. Thus, prenatal androgen manipulations cause cellular-level changes in the primate CNS, which may underlie previously observed effects of these manipulations on behavior.

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Sex difference in Onuf's nucleus homologue in the Asian musk shrew

Cited by 6 publications

References 26 publications

Social Status and Sex Effects on Neural Morphology in Damaraland Mole-Rats, <i>Fukomys damarensis</i>

Social Status and Sex Effects on Neural Morphology in Damaraland Mole-Rats, <i>Fukomys damarensis</i>

Neurochemical features of boar lumbosacral dorsal root ganglion neurons and characterization of sensory neurons innervating the urinary bladder trigone

Effects of sex and prenatal androgen manipulations on Onuf's nucleus of rhesus macaques

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