Noradrenergic transmission and female sexual behavior of guinea pigs.

Abstract

Treatment with the dopamine beta-hydroxylase (DBH) inhibitor U-14,624 (50, 100, or 150 mg/kg) blocked the induction of lordosis behavior be estradiol benzoate (EB) and progesterone (P) in ovariectomized guinea pigs. After treatment with U-14,624 (100 mg/kg), norepinephrine (NE) content of medial basal hypothalamus, preoptic area and cortex was reduced (by 55%) and dopamine (DA) content of medial basal hypothalamus was increased (by 155%) during the period when females treated with EB and P normally display lordosis. Treatment with the NE receptor stimulator clonidine (1.0 mg/kg) restored lordosis behavior in females treated with EB, P, and U-14,624 (100 mg/kg), but the putative DA and serotonin (5-HT) receptor blockers pimozide (1.0 mg/kg) and methysergide (20.0 mg/kg) were ineffective in this respect. Thus, inhibition of lordosis after treatment with U-14,624 appeared to be attributable primarily to a reduction in NE neurotransmission, rather than to increase in DA or 5-HT activity. Because clonidine induced lordosis in females treated with EB, P, and U-14,624, it seemed unlikely that the facilitatory effects of clonidine on lordosis were mediated by activation of presynaptic alpha-adrenergic receptors (i.e. inhibitory NE autoreceptors) rather than by postsynaptic alpha-receptors. In addition, pretreatment with the postsynaptic alpha-adrenergic antagonist phenoxybenzamine (20.0 mg/kg) blocked the facilitation of lordosis by clonidine (1.0 mg/kg) in females primed with EB alone and with EB plus P. Thus, the facilitatory effects of clonidine on lordosis appear to be mediated by activation of postsynaptic alpha-adrenergic (i.e. NE) receptors. The results of this study provide further evidence that NE neurotransmission facilitates the expression of female sexual behavior in guinea pigs.

• Authors: B Nock, H H Feder
• Journal: Brain research (Brain Res) Vol. 166 Issue 2 Pg. 369-80 (Apr 27 1979) ISSN: 0006-8993 [Print] Netherlands
• PMID: 218695 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Receptors, Adrenergic
• Receptors, Dopamine
• Phenoxybenzamine
• Progesterone
• Estradiol
• Dopamine beta-Hydroxylase
• Clonidine
• Dopamine
• Norepinephrine

Topics

• Animals
• Castration
• Cerebral Cortex (metabolism)
• Clonidine (pharmacology)
• Dopamine (metabolism)
• Dopamine beta-Hydroxylase (antagonists & inhibitors)
• Estradiol (pharmacology)
• Female
• Guinea Pigs
• Hypothalamus (metabolism)
• Norepinephrine (metabolism, physiology)
• Phenoxybenzamine (pharmacology)
• Preoptic Area (metabolism)
• Progesterone (pharmacology)
• Receptors, Adrenergic (drug effects)
• Receptors, Dopamine (drug effects)
• Sexual Behavior, Animal (drug effects, physiology)
• Synaptic Transmission (drug effects)