1. Possible Role for Endogenous Oxytocin in Estrogen-Facilitated Maternal Behavior in Rats
- Author
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Joan I. Morrell, Donald W. Pfaff, and Susan E. Fahrbach
- Subjects
medicine.medical_specialty ,Time Factors ,medicine.drug_class ,Oxytocin receptor binding ,Endocrinology, Diabetes and Metabolism ,Peptide hormone ,Biology ,Oxytocin ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Endocrinology ,Pregnancy ,Internal medicine ,Lactation ,medicine ,Animals ,Maternal Behavior ,Estradiol ,Endocrine and Autonomic Systems ,Immune Sera ,Antagonist ,Rats, Inbred Strains ,Rats ,medicine.anatomical_structure ,chemistry ,Estrogen ,Estradiol benzoate ,Ovariectomized rat ,Female ,medicine.drug - Abstract
Intracerebroventricular (i.c.v.) infusions of oxytocin (OXY) induce short-latency maternal behavior in estrogen-primed virgin rats. To investigate if brain OXY might have a role in the onset of maternal behavior at parturition, we have used both antisera to OXY and an analog antagonist of OXY, d(CH2)5-8-ornithine-vasotocin, to reduce the activity of endogenous OXY in a pregnancy-terminated preparation which yields reliable short-latency maternal behavior. Sprague-Dawley rats with lateral ventricle cannulae were ovariectomized and hysterectomized on day 16 of gestation; maternal behavior was stimulated by a s.c. injection of estradiol benzoate (EB). Effects of the i.c.v. infusion of antisera to OXY or of the i.c.v. infusion of d(CH2)5-8-ornithine-vasotocin on the latency to respond to pups were tested by presenting pups 48 h after surgery and EB treatment. Behavioral observations were made for the next 5 h and periodically over the next 5 days. Groups receiving either the antisera to OXY or the analog antagonist had significantly longer latencies to respond to pups than did control groups. In a separate experiment, i.c.v. infusion of d(CH2)5-8-ornithine-vasotocin was shown to have no effect on the performance of maternal behavior in lactating rats 5 days postpartum. These results suggest that OXY may have a role in promoting short-latency maternal behavior in steroid-primed female rats, but that it is probably not involved in sustaining this behavior during lactation.
- Published
- 1985
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