Intracerebroventricular injections of prolactin counteract the antagonistic effect of bromocriptine on rabbit maternal behaviour.
To investigate the participation of prolactin in nest-building and maternal behaviour in rabbits, we administered (from pregnancy day 26 to parturition) rabbit prolactin (rbPRL; or vehicle) intracerebroventricularly (i.c.v.) to primiparous animals injected with bromocriptine subcutaneously (s.c.). Control females (given vehicle s.c. and i.c.v.) built a maternal nest (of straw and body hair) in 77% of cases. This proportion decreased to 19% in the bromocriptine-only group (P < 0.05) and increased to 93% in the group given bromocriptine plus rbPRL (P > 0.05). Maternal behaviour (i.e. the adoption of a crouching posture over the litter inside the nest box) was expressed by 77% of control rabbits, 19% of bromocriptine-only animals (P < 0.05) and 57% of females given bromocriptine plus rbPRL (P > 0.05). Values of nonmaternal activities (i.e. scent-marking, ambulation in an open field) were similar among the three studied groups. These results suggest that prolactin, acting in late pregnancy, plays a major role in the stimulation of nest-building and maternal behaviour in rabbits.
González-Mariscal
G
G
Centro de Investigación en Reproducción Animal: CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, México. gglezm@prodigy.net.mx
Chirino
R
R
Flores-Alonso
J C
JC
Rosenblatt
J S
JS
Beyer
Carlos
C
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D006727:Hormone Antagonists / Q000494:pharmacology*; D007276:Injections, Intraventricular; D007774:Lactation / Q000187:drug effects / Q000502:physiology; D008425:Maternal Behavior / Q000187:drug effects / Q000502:physiology*; D009425:Nesting Behavior / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D011388:Prolactin / Q000008:administration & dosage / Q000502:physiology*; D011817:Rabbits
D018491:Dopamine Agonists; D006727:Hormone Antagonists; D001971:Bromocriptine; D011388:Prolactin