Adolescent and Adult Rats' Aversion to Flavors Previously Paired with Nicotine

Abstract

Despite the high prevalence of adolescent smoking, few studies have examined nicotine sensitivity during this developmental period. In the present study we examined adolescent and adult rats' preference/aversion for a flavor previously paired with nicotine. Paired (nicotine + Kool-Aid) and unpaired (Kool-Aid) solutions were presented in the home cage on alternating nights, with water given during the light phase for six days. A choice test was conducted 24 hr after the last night of conditioning, with both flavors presented simultaneously during the dark cycle. On test day, although the flavor previously paired with nicotine was not preferred at either age, adolescent rats consumed significantly more of the paired flavor than adults. These results suggest that adolescent rats are less sensitive to the aversive properties of nicotine. This finding taken together with adolescents' increased sensitivity to the rewarding properties of nicotine, may result in an increased vulnerability to nicotine dependence.

Adolescent nicotine exposure produces less affective measures of withdrawal relative to adult nicotine exposure in male rats

“…The present study further extends the results of the ICSS study because it utilized a paradigm involving environmental associations with the affective properties of nicotine [5]. Second, the present study is consistent with the finding that adult rats display taste aversion for a solution previously paired with nicotine; however, adolescent rats do not display this taste aversion [27]. Lastly, adolescent rats are less sensitive to the anxiety-inducing effects of withdrawal relative to adults [28].…”

Nicotine Self-Administration, Extinction Responding and Reinstatement in Adolescent and Adult Male Rats: Evidence Against a Biological Vulnerability to Nicotine Addiction during Adolescence

“…The results of these studies suggest that nicotine is more rewarding and less aversive in adolescents compared with adults (Vastola et al, 2002;Belluzzi et al, 2004;Torrella et al, 2004;Wilmouth and Spear, 2004;Shram et al, 2006). There are several possible reasons for this potential discrepancy.…”

“…Adolescent rats share many behavioral and neurobiological characteristics with human adolescents, and have been useful in determining factors contributing to vulnerability to drugs, including nicotine, during this ontogenetic period (Spear, 2000). Using conditioned place preference (CPP) and conditioned taste avoidance (CTA) procedures, we and others reported that adolescent rats are more sensitive to the rewarding effects of nicotine and less sensitive to its aversive effects than adult rats (Vastola et al, 2002;Belluzzi et al, 2004;Torrella et al, 2004;Wilmouth and Spear, 2004;Shram et al, 2006). Furthermore, several investigators reported that adolescent rats may acquire nicotine self-administration faster than adult rats (Levin et al, 2003;Belluzzi et al, 2005;Chen et al, 2007).…”

Adolescent Rats Find Repeated Δ9-THC Less Aversive Than Adult Rats but Display Greater Residual Cognitive Deficits and Changes in Hippocampal Protein Expression Following Exposure

“…Tactile stimulus-elicited vocalization is well documented in cannabinoid-treated rats and is considered an index of a negative drug-induced emotional state (Henriksson and Jarbe, 1971;Giuliani et al, 2000). The reduced aversive effects of cannabinoids in adolescent rats parallel analogous developmental effects observed with alcohol (Philpot et al, 2003) and nicotine (Wilmouth and Spear, 2004). This suggests that certain characteristics of the still-developing adolescent brain may make adolescent rats less sensitive to the use-limiting aversive properties of various drugs of abuse and hence more vulnerable to continued use and addiction.…”