Impairment of acquisition of cocaine self-administration in rats maintained on a high-fat diet

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Abstract

Variations in dietary constituents such as carbohydrate are known to alter psychostimulant function in brain. Relatively few studies have examined the reinforcing effects of psychostimulants in subjects maintained on high-fat diets. The present experiment compared the rate of acquisition of an operant response for intravenous (i.v.) cocaine infusions (0.2 mg/kg) in rats fed either a chow-pellet diet or a 35.9% (by weight) high-fat diet for 45 days prior to cocaine self-administration testing. Rats maintained on a high-fat diet for 45 days exhibited diminished acquisition of cocaine self-administration, and this effect was not a function of dietary-induced obesity. The results suggest that prolonged exposure to a high-fat diet diminishes the efficacy of cocaine reinforcement.

Section snippets

Animals

The studies were approved by the Texas A&M University Laboratory Animal Care Committee. The subjects were adult male Sprague Dawley rats (Harlan Industries: Houston, TX) weighing approximately 285–325 g at the beginning of the study. The rats were single-housed in plastic hanging cages in a colony room maintained at 22.0 ± 1 °C under a 12-h light/dark cycle (lights on at 1200 h) and fed standard chow pellets (or a high-fat test diet) and tap water ad libitum, except when noted below. Rats were

Results

Rats fed a chow-pellet diet or a high-fat diet for 45 days showed variable degrees of weight gain (see Fig. 1). Comparison of average weight gains indicated that the HIGH-FAT rats gained significantly more body weight than did the chow-fed rats during the 45-day exposure period (p < 0.04). In this figure, the weight gains are displayed separately for rats fed the chow diet that either acquired (ACQ-CHOW) or did not acquire cocaine self-administration (NO ACQ CHOW) and for rats fed the high-fat

Conclusions

In the present experiment, rats fed a standard pellet diet showed gradual acquisition of i.v. cocaine self-administration such that 42% of the rats met the acquisition criterion by day 25. This pattern of acquisition is similar to that noted in a chow-fed control group in a recent report from this laboratory (Rocha et al., 2005). In contrast, rats fed a high-fat diet showed diminished acquisition of cocaine self-administration. One explanation for this effect is that maintenance on a high-fat

Acknowledgements

This research was supported by Public Health Service Grants DA13188 and MH65728 to JRN and DA017230 to PJW. We would like to express our gratitude to John Saglime and Leslie Brush for their expert technical assistance in the conduct of the investigation.

References (28)

  • P.J. Wellman et al.

    Meal patterns and body weight after nicotine in male rats as a function of chow or high-fat diet

    Pharmacol Biochem Behav

    (2005)
  • Anonymous

    Nutrient requirements of laboratory animals

    (1995)
  • S.M. Bell et al.

    Food-deprivation increases cocaine-induced conditioned place preference and locomotor activity in rats

    Psychopharmacology (Berl)

    (1997)
  • B.P. Bowman et al.

    Effects of sex and gonadectomy on cocaine metabolism in the rat

    J Pharmacol Exp Ther

    (1999)
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