Low Daytime Light Intensity Disrupts Male Copulatory Behavior, and Upregulates Medial Preoptic Area Steroid Hormone and Dopamine Receptor Expression, in a Diurnal Rodent Model of Seasonal Affective Disorder

We investigated the influence of the extracellular nitric oxide (NO) level on male copulatory behavior. We confirmed the changes of nitrite ([Formula: see text]) and nitrate ([Formula: see text]) in the medial preoptic area (MPOA) by administration of the NO precursorl-arginine (l-Arg, 10 mM) or the NO synthase inhibitor N G-monomethyl-l-arginine (l-NMMA, 10 mM) via a dialysis probe. [Formula: see text] and[Formula: see text] were measured simultaneously by an in vivo microdialysis method coupled with the Griess reaction.l-Arg induced significant elevations of extracellular [Formula: see text]and [Formula: see text].l-NMMA significantly reduced[Formula: see text] and[Formula: see text] levels. We observed male copulatory behavior during infusion ofl-Arg orl-NMMA. The mount rate of male rats significantly increased during infusion ofl-Arg in the MPOA. Administration of l-NMMA reduced the mount rate. These findings suggested that the elevation of extracellular NO in the MPOA facilitates male copulatory behavior of rats, whereas the decrease of NO reduces their copulatory behavior.

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Ovarian steroids alter dopamine receptor populations in the medial preoptic area of female rats: implications for sexual motivation, desire, and behaviour

European Journal of Neuroscience ◽

10.1111/ejn.13121 ◽

2015 ◽

Vol 42 (12) ◽

pp. 3138-3148 ◽

Cited By ~ 12

Author(s):

M. Dean Graham ◽

James Gardner Gregory ◽

Dema Hussain ◽

Wayne G. Brake ◽

James G. Pfaus

Keyword(s):

Dopamine Receptor ◽

Preoptic Area ◽

Sexual Motivation ◽

Medial Preoptic Area ◽

Female Rats ◽

Ovarian Steroids

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Region-, Neuron-, and Signaling Pathway-Specific Increases in Prolactin Responsiveness in Reproductively Experienced Female Rats

Endocrinology ◽

10.1210/en.2010-1220 ◽

2011 ◽

Vol 152 (5) ◽

pp. 1979-1988 ◽

Cited By ~ 29

Author(s):

Annika Sjoeholm ◽

Robert S. Bridges ◽

David R. Grattan ◽

Greg M. Anderson

Keyword(s):

Preoptic Area ◽

Prolactin Receptor ◽

Medial Preoptic Area ◽

Receptor Expression ◽

Dopamine Neurons ◽

Female Rats ◽

Reproductive Experience ◽

Postpartum Disorders ◽

Pregnancy And Lactation ◽

Supraoptic Nuclei

Pregnancy and lactation cause long-lasting enhancements in maternal behavior and other physiological functions, along with increased hypothalamic prolactin receptor expression. To directly test whether reproductive experience increases prolactin responsiveness in the arcuate, paraventricular, and supraoptic nuclei and the medial preoptic area, female rats experienced a full pregnancy and lactation or remained as age-matched virgin controls. At 5 wk after weaning, rats received 2.5, 100, or 4000 ng ovine prolactin or vehicle intracerebroventricularly. The brains underwent immunohistochemistry for the phosphorylated forms of signal transducer and activator of transcription 5 (pSTAT5) or ERK1/2 (pERK1/2). There was a marked increase in pSTAT5 and pERK1/2 in response to prolactin in the regions examined in both virgin and primiparous rats. Primiparous rats exhibited approximately double the number of prolactin-induced pSTAT5-immunoreactive cells as virgins, this effect being most apparent at the higher prolactin doses in the medial preoptic area and paraventricular and supraoptic nuclei and at the lowest prolactin dose in the arcuate nucleus. Dual-label immunohistochemistry showed that arcuate kisspeptin (but not oxytocin or dopamine) neurons displayed increased sensitivity to prolactin in reproductively experienced animals; these neurons may contribute to the reduction in prolactin concentration observed after reproductive experience. There was no effect of reproductive experience on prolactin-induced pERK1/2, indicating a selective effect on the STAT5 pathway. These data show that STAT5 responsiveness to prolactin is enhanced by reproductive experience in multiple hypothalamic regions. The findings may have significant implications for understanding postpartum disorders affecting maternal care and other prolactin-associated pathologies.

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