Sensorimotor gating and dopamine function in postpartum rats

Neuropsychopharmacology. 2007 May;32(5):1021-31. doi: 10.1038/sj.npp.1301222. Epub 2006 Oct 18.


There is much speculation regarding the effects of estrogen withdrawal at the end of pregnancy on forebrain dopamine, however, few studies have directly examine changes in this system postpartum. The present work sought to determine what changes in forebrain dopamine function occur in the postpartum rat. Specifically, prepulse inhibition of the acoustic startle response (PPI) was measured in primiparous female rats on postpartum day 2 (PPD2) or 14 (PPD14) following treatment with saline or the dopamine D2 agonist, quinpirole. Diestrus (DI) females served as controls. Dopamine content and turnover as well as cyclic AMP (cAMP) accumulation were determined within the nucleus accumbens and dorsal striatum in these same females. In addition, circulating levels of plasma corticosterone, estradiol and progesterone were measured. PPI was significantly disrupted in both postpartum groups. This effect was associated with decreased cAMP content within the nucleus accumbens. Quinpirole treatment (0.1 and 0.5 mg/kg) dose-dependently disrupted PPI in DI controls while PPD2 and PPD14 animals demonstrated reduced sensitivity to the D2 agonist. PPD14 animals demonstrated increased startle amplitude, an effect that was attenuated by quinpirole treatment. PPD14 females were also less sensitive to quinpirole-mediated reductions in DA turnover within the nucleus accumbens and both PPD2 and PPD14 females had an attenuated response to the stimulatory effects of quinpirole on corticosterone secretion. Collectively these findings suggest that the postpartum period is associated with reduced sensorimotor gating and altered forebrain DA systems, which may be related to shifts in circulating hormones.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Brain Chemistry / drug effects
  • Brain Chemistry / physiology*
  • Corticosterone / blood
  • Corticosterone / metabolism
  • Cyclic AMP / metabolism
  • Dopamine / metabolism*
  • Dopamine Agonists / pharmacology
  • Dose-Response Relationship, Drug
  • Female
  • Gonadal Steroid Hormones / blood
  • Lactation / physiology
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Neostriatum / drug effects
  • Neostriatum / metabolism
  • Neostriatum / physiopathology
  • Neural Inhibition / drug effects
  • Neural Inhibition / physiology*
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / metabolism*
  • Nucleus Accumbens / physiopathology
  • Postpartum Period / physiology*
  • Pregnancy
  • Quinpirole / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D2 / agonists
  • Receptors, Dopamine D2 / metabolism
  • Reflex, Startle / drug effects
  • Reflex, Startle / physiology*


  • Dopamine Agonists
  • Gonadal Steroid Hormones
  • Receptors, Dopamine D2
  • Quinpirole
  • Cyclic AMP
  • Dopamine
  • Corticosterone