The propensity for nonregulatory ingestive behavior is related to differences in dopamine systems: Behavioral and biochemical evidence.

Abstract

Previous research has shown that animals predisposed to eat and drink in response to electrical stimulation of the lateral hypothalamus (ESLH) are similarly predisposed to drink excessively when tested for schedule-induced polydipsia. The eating and drinking elicited by both experimental paradigms appears to be unrelated to homeostatic need and has been called nonregulatory ingestive behavior. In this study, the relation between properties of dopaminergic neural systems and the predisposition to exhibit nonregulatory ingestive behavior was investigated. It was found that rats that eat and drink during ESLH show greater behavioral sensitization to a series of amphetamine injections that those that do not exhibit ingestive behavior during ESLH. In addition, footshock stress produced a greater increase in forebrain dopamine utilization in rats that engaged in nonregulatory ingestive behavior. This evidence is consistent with the hypothesis that there are individual differences in the responsiveness of forebrain dopamine systems that are related to the behavioral predisposition to exhibit nonregulatory ingestive behavior.

Basal local cerebral glucose utilization is not altered after behavioral sensitization to quinpirole

“…However, a lack of effect of amphetamine sensitization on basal dopamine content, neurotransmission, or receptor density has also been reported in a number of studies similar to that observed in this study, even though sensitized behavioral effects were observed when a challenge dose was given [9,[11][12][13][15][16][17]23,25,26]. Likewise, although some behavioral effects of quinpirole-sensitization, such as more repetitive travel in the open field and more perseveration during extinction in the water maze, persist for as much as 3 months after the last administration of quinpirole, other behavioral effects, such as increased overall activity level in the open field, do not [7].…”

Poor inhibitory control and neurochemical differences in high compulsive drinker rats selected by schedule-induced polydipsia

“…Previous studies have shown that SIP could be associated with higher DA utilization in the nucleus accumbens (Mittleman et al 1986). The current study has also demonstrated that the SIP experience could also be associated with changes in monoaminergic activity basal levels in different mesolimbicortical regions compared to unexposed SIP animals.…”

Stereotypies: a critical review

“…The stimulants may be acting as stressors themselves (e.g. Mittleman et al 1986). In some cases stressful treatments do not enhance the development of stereotypy, and may even inhibit or disrupt it ; and e.g.…”

“…They may also involve opioid systems to different extents (see Robbins & Sahakian 1981). Furthermore, the various stereotypies elicited by increased or repeated dosage of one drug show different patterns of sensitization (Eichler et al 1980), and may, as they change from complex to more simple forms, have different neurophysiological bases (reviewed by Robbins & Sahakian 1981; see also Mittleman et al 1986). …”

“…Hinde 1962;Wolpe 1967;Robbins 1976;Ridtey & Baker 1982); and they may reveal fundamental differences between individuals in terms of dopamine systems, general tendencies to persist with behaviour, and styles of coping with adversity (e.g. Mittleman et al 1986;Dantzer 1989). Furthermore, it is essential to understand stereotypies if we are to improve practices of husbandry in ways that abolish the causes, and not just the symptoms (Odberg 1978;Ridley & Baker 1982;Dantzer 1990 McCune, Mike Mendl, F r a n k Odberg, Trevor Robbins, Jeff Rushen, Michael Simpson and Nigel W a r b u r t o n for invaluable discussion and comments.…”