You are here:
INCREASED SUSCEPTIBILITY OF THE SPONTANEOUSLY HYPERTENSIVE RAT TO CHLORPYRIFOS, AN ORGANOPHOSPHATE PESTICIDE.
Citation:
Smith, E. G., B Padnos, AND C J. Gordon. INCREASED SUSCEPTIBILITY OF THE SPONTANEOUSLY HYPERTENSIVE RAT TO CHLORPYRIFOS, AN ORGANOPHOSPHATE PESTICIDE. Presented at Experimental Biology 2002, New Orleans, LA, 4/20-24/2002.
Description:
Hypertension and hypothermia are common symptoms in rats exposed to chlorpyrifos (CHP), an organophosphate (OP)-based pesticide. CHP inhibits acetylcholinesterase (AChE) activity resulting in central and peripheral stimulation of cholinergic pathways involved in blood pressure (BP) regulation and other autonomic functions. The spontaneously hypertensive rat (SHR) is more sensitive to cholinergic stimulation. We hypothesized that SHRs are more susceptible when exposed to CHP. BP was monitored by radiotelemetry in SHR and WKY controls following exposure to CHP (10 mg/kg or 25 mg/kg p.o.). Plasma AChE activity was measured 4 hr after exposure in another set of rats. SHRs exhibited greater sensitivity to CHP as was evident by a greater and sustained elevation in diastolic, mean, and systolic BP. The rise in BP lasted ~70 hrs in SHRs and ~42 hrs in WKYs. However, AChE inhibition 4 hr after exposure in SHRs receiving 25 mg/kg or 10 mg/kg was not different from WKYs.
Interestingly, baseline AChE activity was 25% higher in SHRs. The hypothermic response to CHP was similar in magnitude for both strains but the duration was longer in WKYs. The data suggest that individuals with a genetic predisposition to hypertension, which is associated with an enhanced sensitivity to cholinergic stimulation, may manifest an increased risk when exposed to OP-pesticides. Moreover, plasma AChE inhibition is not directly correlated with the cardiovascular risk from exposure to CHP. This abstract does not necessarily reflect U.S. EPA policy.