TY - JOUR
T1 - Methamphetamine facilitates female sexual behavior and enhances neuronal activation in the medial amygdala and ventromedial nucleus of the hypothalamus
AU - Holder, Mary K.
AU - Hadjimarkou, Maria M.
AU - Zup, Susan L.
AU - Blutstein, Tamara
AU - Benham, Rebecca S.
AU - McCarthy, Margaret M.
AU - Mong, Jessica A.
PY - 2010/2
Y1 - 2010/2
N2 - Methamphetamine (MA) abuse has reached epidemic proportions in the United States. Users of MA report dramatic increases in sexual drive that have been associated with increased engagement in risky sexual behavior leading to higher rates of sexually transmitted diseases and unplanned pregnancies. The ability of MA to enhance sexual drive in females is enigmatic since related psychostimulants like amphetamine and cocaine appear not to affect sexual drive in women, and in rodents models, amphetamine has been reported to be inhibitory to female sexual behavior. Examination of MA's effects on female sexual behavior in an animal model is lacking. Here, using a rodent model, we have demonstrated that MA enhanced female sexual behavior. MA (5 mg/kg) or saline vehicle was administered once daily for 3 days to adult ovariectomized rats primed with ovarian steroids. MA treatment significantly increased the number of proceptive events and the lordosis response compared to hormonally primed, saline controls. The effect of MA on the neural circuitry underlying the motivation for sexual behavior was examined using Fos immunoreactivity. In the medial amygdala and the ventromedial nucleus of the hypothalamus, nuclei implicated in motivated behaviors, ovarian hormones and MA independently enhance the neuronal activation, but more striking was the significantly greater activation induced by their combined administration. Increases in dopamine neurotransmission may underlie the MA/hormone mediated increase in neuronal activation. In support of this possibility, ovarian hormones significantly increased tyrosine hyroxylase (the rate limiting enzyme in dopamine synthesis) immunoreactivity in the medial amygdala. Thus our present data suggest that the interactions of MA and ovarian hormones leads to changes in the neural substrate of key nuclei involved in mediating female sexual behaviors, and these changes may underlie MA's ability to enhance these behaviors.
AB - Methamphetamine (MA) abuse has reached epidemic proportions in the United States. Users of MA report dramatic increases in sexual drive that have been associated with increased engagement in risky sexual behavior leading to higher rates of sexually transmitted diseases and unplanned pregnancies. The ability of MA to enhance sexual drive in females is enigmatic since related psychostimulants like amphetamine and cocaine appear not to affect sexual drive in women, and in rodents models, amphetamine has been reported to be inhibitory to female sexual behavior. Examination of MA's effects on female sexual behavior in an animal model is lacking. Here, using a rodent model, we have demonstrated that MA enhanced female sexual behavior. MA (5 mg/kg) or saline vehicle was administered once daily for 3 days to adult ovariectomized rats primed with ovarian steroids. MA treatment significantly increased the number of proceptive events and the lordosis response compared to hormonally primed, saline controls. The effect of MA on the neural circuitry underlying the motivation for sexual behavior was examined using Fos immunoreactivity. In the medial amygdala and the ventromedial nucleus of the hypothalamus, nuclei implicated in motivated behaviors, ovarian hormones and MA independently enhance the neuronal activation, but more striking was the significantly greater activation induced by their combined administration. Increases in dopamine neurotransmission may underlie the MA/hormone mediated increase in neuronal activation. In support of this possibility, ovarian hormones significantly increased tyrosine hyroxylase (the rate limiting enzyme in dopamine synthesis) immunoreactivity in the medial amygdala. Thus our present data suggest that the interactions of MA and ovarian hormones leads to changes in the neural substrate of key nuclei involved in mediating female sexual behaviors, and these changes may underlie MA's ability to enhance these behaviors.
KW - Dopamine neurotransmission
KW - Lordosis
KW - Neuronal activation
KW - Proceptive behavior
KW - Tyrosine hydroxylase
UR - http://www.scopus.com/inward/record.url?scp=73949092393&partnerID=8YFLogxK
U2 - 10.1016/j.psyneuen.2009.06.005
DO - 10.1016/j.psyneuen.2009.06.005
M3 - Article
C2 - 19589643
AN - SCOPUS:73949092393
SN - 0306-4530
VL - 35
SP - 197
EP - 208
JO - Psychoneuroendocrinology
JF - Psychoneuroendocrinology
IS - 2
ER -