Table 1. Summary of experimental procedure.

Groups	Pretreatment	After-treatment
	(drink, 7 d)	(i.p., 2 times/d, 3 d)
		a.m.	p.m.
Saline (control)	water	saline	saline
2 mg/kg cocaine	water	saline	2 mg/kg cocaine
20 mg/kg cocaine	water	saline	20 mg/kg cocaine
Nicotine	nicotine	saline	saline
Nicotine +2 mg/kgcocaine	nicotine	saline	2 mg/kg cocaine
Nicotine +20 mg/kgcocaine	nicotine	saline	20 mg/kg cocaine