Intravenous morphine self-administration by rats with low versus high saccharin preferences

Abstract

An experiment was performed to determine the relationship between saccharin preference and the self-administration of morphine via the oral and intravenous routes. On the basis of voluntary intake of a saccharin solution by male rats, low and high preference groups were formed. Rats selected for high saccharin preference self-administered more morphine intravenously than rats selected for low preference. The two groups did not differ in oral morphine intake. The positive relationship between the intake of saccharin and intravenous morphine self-administration may be due to their mediation by a common mechanism. Measures of taste sensitivity or preference may be useful in identifying individuals at risk for drug abuse.

The melanocortin receptor agonist MTII augments the rewarding effect of amphetamine in ad-libitum-fed and food-restricted rats

“…This phenomenon parallels the enhancement, by food restriction, of drug self-administration (Carroll and Meisch 1984) and conditioned place preference (Bell et al 1997), and appears to reflect an increase in sensitivity of the neural substrate for drug reward (Cabeza de Vaca and Carr 1998). The augmentation of drug reward by food restriction is just one of numerous observations that support an association between drug-seeking and ingestive behavior (Sills et al 1998;Gosnell et al 1995;Comer et al 1996;Sills and Vaccarino 1994;Gosnell 2000). Although the physiological mechanisms underlying the augmentation of drug reward by food restriction have not been established, the augmented rewarding effect of amphetamine in food-restricted subjects is associated with increased cfos expression in limbic forebrain dopamine terminal areas (Carr and Kutchukhidze 2000).…”

Reward systems and food intake: role of opioids

“…[33][34][35] Furthermore, the rats either selected or bred for high or low sweet intake show corresponding differences in the acquisition or amount of self-administered amphetamine, cocaine, and morphine. [36][37][38][39] In humans, opiate-dependent subjects on methadone maintenance report higher consumption of sweets than control subjects, 40 and subjects diagnosed with alcohol dependence or cocaine abuse/dependence tend to prefer sweeter sucrose solutions than controls. 41,42 After reviewing the similarities between the effects of sugar ingestion and those related to drug addiction, Avena et al 43 conclude that under some circumstances, sugar can be addictive.…”

Sucrose intake predicts rate of acquisition of cocaine self-administration

“…In addition, rats selectively bred for high or low ethanol intake show parallel differences in saccharin intake (Sinclair et al 1992). Gosnell et al (1995) reported that rats with a high preference for saccharin self-administered more morphine than rats with a low preference. In human subjects, the peak of the sucrose concentration-preference curve was at a higher concentration for abstinent alcoholics than for controls (Kampov-Polevoy et al 1997).…”