Pregnancy enhances cocaine-induced stimulation of uterine contractions in the chronically instrumented rat.
OBJECTIVE
Our purpose was to test whether cocaine stimulates uterine activity in nonpregnant and pregnant rats.


METHODS
The carotid artery and jugular vein were chronically catheterized, and a microballoon probe was inserted into the uterine cavity of 15 pregnant and 14 nonpregnant female rats. Conscious animals received a bolus dose of either cocaine or saline solution intravenously. Cardiovascular and uterine contractile responses were studied.


RESULTS
Cocaine (2.5 mg/kg) induced a marked increase in uterine activity and arterial blood pressure in both pregnant and nonpregnant animals without producing systemic toxicity. The maximum change in uterine contractions was greater in the pregnant group than in the nonpregnant group, and blood pressure responses were transient in both.


CONCLUSIONS
This study is the first demonstration that cocaine stimulates the rat uterus in vivo, with a greater increase in contractions in pregnant compared with nonpregnant animals. These differences are not related to the hemodynamic response or pharmacokinetic profile of cocaine.
Nakahara
K
K
Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Iso
A
A
Chao
C R
CR
Cooper
T B
TB
Morishima
H O
HO
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D009294:Narcotics / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014590:Uterine Contraction / Q000187:drug effects*
D009294:Narcotics; C005618:benzoylecgonine; D003042:Cocaine