Sex differences in neural activation following different routes of oxytocin administration in awake adult rats. (July 2017)

• Record Type: Journal Article
• Authors: Dumais, Kelly M.; Kulkarni, Praveen P.; Ferris, Craig F.; Veenema, Alexa H.
• Is Part Of: Psychoneuroendocrinology. Volume 81(2017)
• Page Start: 52
• Page End: 62
• Publication Date: 2017-07
• Subjects: Oxytocin -- Sex differences -- Amygdala -- Nucleus accumbens -- fMRI -- Rat; Psychoneuroendocrinology -- Periodicals; Endocrinology -- Periodicals; Neurology -- Periodicals; Psychiatry -- Periodicals; Neuropsychoendocrinologie -- Périodiques; 616.8
• DOI: 10.1016/j.psyneuen.2017.04.003
• Languages: English
• ISSNs: 0306-4530

Abstract

Highlights: BOLD activation was analyzed in male and female rat brains after oxytocin injection. Males showed a greater volume of activation following oxytocin compared to females. Central oxytocin induced sex differences in more regions than peripheral oxytocin. Males showed more activation in the nucleus accumbens following central oxytocin. Females showed more activation in the amygdala following central oxytocin. Abstract: The neuropeptide oxytocin (OT) regulates social behavior in sex-specific ways across species. OT has promising effects on alleviating social deficits in sex-biased neuropsychiatric disorders. However little is known about potential sexually dimorphic effects of OT on brain function. Using the rat as a model organism, we determined whether OT administered centrally or peripherally induces sex differences in brain activation. Functional magnetic resonance imaging was used to examine blood oxygen level-dependent (BOLD) signal intensity changes in the brains of awake rats during the 20 min following intracerebroventricular (ICV; 1 μg/5 μl) or intraperitoneal (IP; 0.1 mg/kg) OT administration as compared to baseline. ICV OT induced sex differences in BOLD activation in 26 out of 172 brain regions analyzed, with 20 regions showing a greater volume of activation in males (most notably the nucleus accumbens and insular cortex), and 6 regions showing a greater volume of activation in females (including the lateral and central amygdala). IP OT also elicited sex differences in BOLD activation with a greater volume of activation in males, but this activation was found in different and fewer (10) brain regions compared to ICV OT. In conclusion, exogenous OT modulates neural activation differently in male versus female rats with the pattern and magnitude, but not the direction, of sex differences depending on the route of administration. These findings highlight the need to include both sexes in basic and clinical studies to fully understand the role of OT on brain function.