Restricted exposure of mice to primer pheromones coincident with prolactin surges blocks pregnancy by changing hypothalamic dopamine release

in Reproduction
Authors:
A. E. Rosser
Search for other papers by A. E. Rosser in
Current site
Google Scholar
PubMed
Close
,
C. J. Remfry
Search for other papers by C. J. Remfry in
Current site
Google Scholar
PubMed
Close
, and
E. B. Keverne
Search for other papers by E. B. Keverne in
Current site
Google Scholar
PubMed
Close
View More View Less
Free access

Summary. 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 β-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.

Keywords: pheromones; pregnancy block; critical exposure time; dopamine; mouse

 

  • Collapse
  • Expand

     An official journal of

    Society for Reproduction and Fertility