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.
Easton
A
A
Department of Neurobiology and Behavior, Rockefeller University, New York, NY 10021, USA. amy.easton@gmail.com
Dwyer
E
E
Pfaff
D W
DW
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