title: Restricted exposure of mice to primer pheromones coincident with prolactin surges blocks pregnancy by changing hypothalamic dopamine release.
abstract: Exposure of recently mated female mice to strange male urine revealed that exposure for 8 h was sufficient to produce pregnancy block providing exposure is for two 4-h periods coincident with prolactin surges. Exposure for 8 h between prolactin surges or one 4-h exposure coincident with either the nocturnal or the diurnal prolactin surge was without effect. When bromocriptine, a dopamine agonist, was given coincident with the nocturnal and diurnal prolactin surges, it was equally effective, but the opiate antagonist (naltrexone) administered in a similar manner was without effect. This result indicates that pheromonal action is through excitation of the tuberoinfundibular neurones rather than by inhibition of beta-endorphin neurones. Further evidence for dopamine involvement in pregnancy block is demonstrated by showing DOPA accumulation in the medio-basal hypothalamus following exposure to male urinary pheromones after dihydroxybenzylhydrazine (DHBH) administration, which blocks the enzyme DOPA-decarboxylase. Taken together, this series of experiments provides convincing evidence for the dopamine inhibition of prolactin release being the final pathway for pheromone action in the context of pregnancy block.
authors.affiliation: Department of Anatomy, University of Cambridge, UK.
authors.forename: A E
authors.initials: AE
authors.lastname: Rosser
authors.forename: C J
authors.initials: CJ
authors.lastname: Remfry
authors.forename: E B
authors.initials: EB
authors.lastname: Keverne
mesh_terms: D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D009271:Naltrexone / Q000494:pharmacology; D010675:Pheromones / Q000494:pharmacology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011388:Prolactin / Q000378:metabolism*; D012724:Sex Attractants / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D010675:Pheromones; D012724:Sex Attractants; D001971:Bromocriptine; D009271:Naltrexone; D004295:Dihydroxyphenylalanine; D011388:Prolactin; D004298:Dopamine