EFFECTS OF PARTURITION AND MATERNAL EXPERIENCE ON NORADRENALINE AND ACETYLCHOLINE-RELEASE IN THE OLFACTORY-BULB OF SHEEP

Acetylcholine (ACh) and noradrenaline (NA) release in the olfactory bu lb (OB) of ewes was monitored using microdialysis. Both ACh and NA rel ease increased at parturition in multiparous but not in primiparous ew es. However, vaginocervical stimulation performed 6 hr postpartum indu ced an increase of ACh and NA-release in both primiparous and multipar ous ewes, indicating that a maturation process had occurred. Finally, pharmacological challenges to the ACh and NA inputs revealed different ial responsiveness between nulliparous and multiparous nongestant ewes . These results suggest that the first parturition induces changes in neural circuitry involving ACh and NA inputs to the OB.