Relation between eating evoked by lateral hypothalamic stimulation and tail pinch in different rat strains

Abstract

The similarity between the behaviors evoked by tail pinch (TP) and electrical stimulation of the lateral hypothalamus (ESLH) has been noted by many investigators. Evidence is presented for a possible inverse relationship between the probability that ESLH would evoke eating and the readiness to eat in response to TP in six different rat populations (High and Low lines of the LC1 and LC2Hebrew University Strains, Sprague-Dawley, and Long-Evans). Discussion of these results emphasizes differences in intensity between ESLH and TP stimulation and differences in emotionality among rat populations.

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

“…Of particular interest here are individual differences in the predisposition to show nonregulatory ingestive behavior. Not all animals display nonregulatory ingestive behavior when activated, or they do not display it to the same degree (Bachus & Valenstein, 1979; Koob, Fray, & Iversen, 1976; Mittleman & Valenstein, 1981, 1984; Valenstein, 1969; Valenstein, Cox, & Kakolewski, 1970; Valenstein, Lieblich, Divar, Cohen, & Bachus, 1982; Wise, 1971). In exploring what factors might-predispose animals to display nonregulatory ingestive behavior, animals that do eat and drink during electrical stimulation of the lateral hypothalamus ( ESLH -pos) and those that do not ( ESLH -neg) have been compared in a variety of different experimental paradigms; for example, ESLH -pos rats exhibit significantly more drinking during SIP tests than ESLH -neg rats, results indicating a consistency across two experimental paradigms (Mittleman & Valenstein, 1984).…”

Opiate reinforcement and naloxone aversion, as revealed by place preference paradigm, in two strains of rats

“…Such an approach enables a correlational study of different phenomena that could not be investigated using within-subject design, due to methodological difficulties. The LC2-Lo and LC2-Hi lines have been developed through a bidirectional selection for low and high rates of lateral hypothalamic self-stimulation (Lieblich et al 1978), and were later found to differ in several motivational tendencies (Lieblich et al 1980;Ganchrow et al 1981 ;Valenstein et al 1982;Moreau et al 1984). It was reasoned that if one of the two lines would display a more pronounced change in preference for an environment paired with opiates, along with a more pronounced aversive effect of naloxone, then the existence of a hypothetical common factor underlying both phenomena would be supported.…”