Elsevier

Alcohol

Volume 28, Issue 1, August 2002, Pages 1-7
Alcohol

High-priority communication
Repeated nicotine injections decrease operant ethanol self-administration,☆☆

https://doi.org/10.1016/S0741-8329(02)00238-0Get rights and content

Abstract

Nicotine and alcohol are two of the most used drugs in the United States. However, it is not clear whether the co-use of these drugs is due to pharmacological or environmental reasons, or perhaps related to both. Although results from previous studies in animal models seem to indicate that nicotine has an effect on ethanol consumption, little has been done to determine how nicotine affects appetitive and consummatory phases of ethanol self-administration. In this study, we examined the effect of repeated treatment with nicotine (0, 0.35, and 0.7 mg/kg, s.c.), given 30 min before a daily operant session, on appetitive and consummatory phases of Long–Evans rats self-administering 10% (vol./vol.) ethanol in a sipper-tube model. Ethanol intake (consummatory phase) decreased at both doses of nicotine tested, and lever pressing (appetitive phase) decreased after injection of the high dose of nicotine. These results support the suggestion that nicotine affects ethanol self-administration. However, in this model, the findings demonstrate a reduction in drinking, rather than the enhancement that has been shown in findings obtained from other studies.

Introduction

The co-use of tobacco and alcohol has long been noted in human beings. Results of studies have shown that the majority of alcohol-dependent persons are tobacco users (Walton, 1972) and that alcoholism is 10 times more common among smokers than nonsmokers (DiFranza & Guerrera, 1990). Findings from studies with animals have shown that experimenter-delivered nicotine affects the consumption of ethanol. This has been shown with both acute and repeated-dosing designs. Acute treatment with nicotine decreases or has no effect on the amount of ethanol consumed by rats Dyr et al. 1999, Katner et al. 1997. When nicotine was administered once daily, after the daily ethanol self-administration session, it had no effect on the amount of ethanol consumed (Nadal & Samson, 1999). However, results of other studies have shown that repeated treatment of rats with nicotine increased consumption of ethanol Blomqvist et al. 1996, Lê et al. 2000. This increase in consumption can be attenuated by delivery of central nicotinic acetylcholine antagonists, supporting the suggestion that the increase in ethanol intake is related to action at the nicotinic acetylcholine receptor Blomqvist et al. 1993, Smith et al. 1999. Although the effect of nicotine on consumption of ethanol has been examined in previous studies, there is little information on how nicotine specifically alters ethanol intake.

Ethanol self-administration can be divided conceptually into two types of behavioral processes: appetitive and consummatory. Appetitive behaviors relate to “seeking” and obtaining ethanol and are measured as lever pressing in rat operant models. “Craving” in the alcoholic condition in human beings could be considered an appetitive behavior. Appetitive responding is controlled by a number of factors, including environmental cues, time since the last availability of the reinforcer, and physical dependence on ethanol [for a review of this concept, see Samson et al. (2000)]. Consummatory behaviors are involved with the ingestion of the alcohol. Factors that may affect responding during the consummatory phase include recent consumption of food and water or other fluids, environmental cues, time since the last availability of the reinforcer, sensitivity or tolerance to the reinforcer, and amount of reinforcer already consumed in the ongoing drinking bout (satiety).

We have recently used an operant method of ethanol self-administration with sipper tubes for delivery of ethanol, in which it is possible to separate appetitive and consummatory phases Samson et al. 1998, Samson et al. 1999, Samson et al. 2000. The sipper-tube paradigm has been used to examine the effects of several pharmacological agents on appetitive and consummatory components of ethanol self-administration Czachowski et al. 2001a, Czachowski et al. 2001b, Freedland et al. 2001, Sharpe & Samson 2001. In the current study, we used the sipper-tube model to determine how nicotine may affect ethanol self-administration. Specifically, the effect of repeated experimenter-delivered nicotine on appetitive and consummatory components of ethanol self-administration was examined.

Section snippets

Animals

Male, Long–Evans rats (n = 6) were housed individually in stainless steel hanging cages in a room with a 12 h:12 h light:dark cycle with lights on at 0600. Food and water were available ad libitum in the home cage except where noted in the training procedure. The protocol was approved by the institutional animal care and use committee of Wake Forest University School of Medicine, and rats were cared for according to guidelines set forth in Guide for the Care and Use of Laboratory Animals

Results

For the 5 days preceding nicotine treatment, ethanol intake was 0.73 ± 0.04 g/kg, and all rats completed the response requirement on all sessions during the baseline days. Saline treatment did not change any lick or lever-pressing measures from the baseline data, nor did it alter completion of the response requirement.

Discussion

In the present study, low- and high-dose experimenter-delivered nicotine decreased ethanol intake. Nicotine did not affect the onset of drinking, but, rather, terminated an otherwise normal drinking pattern earlier in the consummatory bout compared with findings for vehicle treatment. On the basis of these results, we hypothesize that nicotine is interfering with the maintenance of the consummatory bout while having little effect on the onset of drinking. With the use of the sipper-tube model,

Acknowledgements

This research was supported by grants F31 AA05566 to ALS and R37 AA06845, K05 AA00142, and P50 AA11997 to HHS from the National Institute on Alcohol Abuse and Alcoholism from the National Institutes of Health. The authors wish to thank Ann Chappell, Brooke Legg, and Dr. Cristine Czachowski for their aid in completing this study.

References (29)

  • V Blaha et al.

    Systemic nicotine administration suppresses food intake via reduced meal sizes in both male and female rats

    Acta Medica (Hradec Kralove)

    (1998)
  • C.L Czachowski et al.

    Effects of raclopride in the nucleus accumbens on ethanol seeking and consumption

    Alcohol Clin Exp Res

    (2001)
  • C.L Czachowski et al.

    Effects of acamprosate on ethanol-seeking and self-administration in the rat

    Alcohol Clin Exp Res

    (2001)
  • J.R DiFranza et al.

    Alcoholism and smoking

    J Stud Alcohol

    (1990)
  • Cited by (34)

    • The incentive amplifying effects of nicotine: Roles in alcohol seeking and consumption

      2022, Advances in Pharmacology
      Citation Excerpt :

      The simplicity of this design is likely one of the reasons why this approach has historically been one of the most widely employed. For example, a number of early studies from Samson and colleagues have demonstrated that alcohol intake in rats is acutely suppressed when measured following subcutaneous injections of nicotine (Hendrickson, Zhao-Shea, Pang, Gardner, & Tapper, 2010; Nadal & Samson, 1999; Sharpe & Samson, 2002). Nicotine is anorexigenic (Jo, Talmage, & Role, 2002), which likely suppresses alcohol intake during early phases of nicotine exposure.

    • Nicotine as a discriminative stimulus for ethanol use

      2018, Drug and Alcohol Dependence
      Citation Excerpt :

      These effects are often thought to be due to nicotine increasing ethanol seeking and use by directly enhancing the reinforcing effect of ethanol (Doyon et al., 2013). For example after a history of nicotine exposure outside of the context where drinking occurs, nicotine re-exposure increases ethanol consumption and preference, but does not affect cue-induced reinstatement of ethanol responding (Clark et al., 2001; Ericson et al., 2000; Kemppainen et al., 2009; Leão et al., 2015; Madayag et al., 2017; c.f. Sharpe and Samson, 2002). Smoking and drinking most often co-occur in humans, resulting in conditions where each can come to serve as a discriminative stimulus for use of the other (Higgins and Silverman, 1999; DiFranza and Guerrera, 1990).

    • Enhanced Tobacco Use Vulnerability in Adolescents, Females, and Persons With Diabetes

      2017, Negative Affective States and Cognitive Impairments in Nicotine Dependence
    • Cigarettes and alcohol: The influence of nicotine on operant alcohol self-administration and the mesolimbic dopamine system

      2015, Biochemical Pharmacology
      Citation Excerpt :

      Nicotine can produce either anxiolytic or anxiogenic effects depending on the dose [61]; therefore, the influence of nicotine over early ethanol drinking could be due in part to nicotine’s anxiogenic properties. In terms of operant ethanol self-administration that is already established or maintained, several studies have examined ethanol intake in response to nicotine exposure [20,21,24,25,62,63]. In these studies, the nicotine was administered to rats by repeated subcutaneous injections prior to daily self-administration sessions.

    View all citing articles on Scopus

    A paper published as a high-priority communication is one that reviewers have identified as being of high scientific significance and have recommended that the study findings should be communicated to the scientific community as soon as possible.

    ☆☆

    Editor: T.R. Jerrells

    View full text