Acute nicotine reduces and repeated nicotine increases spontaneous activity in male and female Lewis rats.
The Lewis (LEW) strain of rat appears more sensitive to nicotine than other strains in self-administration, conditioned place preference, and drug discrimination behavioral studies. The present study sought to further evaluate the behavioral effects of chronic nicotine treatment in the LEW strain by assessing spontaneous activity, which has consistently revealed sensitization to chronic nicotine administration in Sprague Dawley (SD) rats. High active and low active male and female LEW rats (N=8 per group) were treated twice daily with either nicotine (0.4 mg/kg, sc) or vehicle for 14 consecutive days. Regardless of baseline activity level or sex, spontaneous activity was significantly decreased, compared to saline-treated rats, after a single nicotine injection. However, spontaneous activity increased in both low- and high-activity rats (both sexes) over the two weeks of nicotine administration to levels that were significantly higher than saline-treated rats. Based on these findings, acute and chronic nicotine administration had greater suppressive and enhancing effects on spontaneous activity in LEW rats compared to other strains of rats previously studied. These results further clarify the behavioral sensitivity of the LEW strain of rat to nicotine exposure and lend credence to the role of genetics in the individual susceptibility to nicotine dependence.
Prus
Adam J
AJ
Psychology Department, Northern Michigan University, Marquette, MI, USA.
Vann
Robert E
RE
Rosecrans
John A
JA
James
John R
JR
Pehrson
Alan L
AL
O'Connell
Mary M
MM
Philibin
Scott D
SD
Robinson
Susan E
SE
D000704:Analysis of Variance; D000818:Animals; D003627:Data Interpretation, Statistical; D005260:Female; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011917:Rats, Inbred Lew
D018722:Nicotinic Agonists; D009538:Nicotine