Estradiol and orexin-2 saporin actions on multiple forms of behavioral arousal in female mice.
Estrogens modulate almost all aspects of female behavioral arousal; however, apart from that of sexual behavior, the neurobiology of female arousal remains unclear. Because orexins-hypocretins are neurotransmitters known to be important for behavioral arousal, the authors hypothesized that orexins may be a target for estrogen. Gonadectomized female mice received an intracerebral injection of either phosphate-buffered saline, the neurotoxin saporin (SAP), or the orexin-2-saporin conjugate (OXSAP) in the lateral hypothalamus. SAP- and OXSAP-treated mice were also divided into groups receiving either estradiol capsules or oil capsules. Mice were tested in 3 behavioral tests measuring different modes of arousal: sensory responsiveness, running wheel activity, and fearfulness. OXSAP mice showed decreases in sensory responsiveness and fearfulness concomitant with a reduction in orexin cell number. Estradiol affected all behaviors tested but decreased fearfulness only when combined with OXSAP treatment. These data indicate that estrogens modulate orexins' effects on fearfulness.
Department of Neurobiology and Behavior, Rockefeller University, New York, NY 10021, USA. amy.easton@gmail.com
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D000818:Animals; D001143:Arousal / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000166:cytology* / Q000187:drug effects*; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005239:Fear / Q000187:drug effects*; D005260:Female; D007267:Injections; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D009479:Neuropeptides / Q000008:administration & dosage / Q000494:pharmacology*; D000068797:Orexins; D010865:Pilot Projects; D049231:Saposins / Q000008:administration & dosage / Q000494:pharmacology*
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D049231:Saposins; D004958:Estradiol