Lesions of the lateral parabrachial area block the aversive component and induced-flavor preference for the delayed intragastric administration of nutrients in rats: Effects on subsequent food and water intake

Abstract

The aim of this study was to examine the function of the lateral parabrachial area (LPB) in relation to the intragastric administration of nutrients. The consumption of flavors associated with intragastric nutrient administration and the subsequent food and water intake were measured in rats with lesions in the LPB. The results showed that bilateral LPB lesions prevented development of aversions and induced flavor preference when there was a delay between the presentation of a flavor and the intragastric administration of nutrients. However, these lesions did not disrupt development of the aversive process when there was no delay between the presentations. Likewise, the LPB lesions increased subsequent food intake when there was a delay but not when there was no delay between the presentations. In contrast, the water intake was reduced in both situations. These results are interpreted in terms of a dual visceral system for processing the intragastric effects of foods.

Enteral Feeding: Brain-Visceral Interactions in the Processing of Nutrients

“…Studies using this technique have demonstrated that the direct administration of complex food into the gastric cavity is a powerful way to establish flavor-conditioned aversions [66,80,[84][85][86]. Thus, when rats were subjected to a discriminative flavor learning task using whole milk as visceral stimulus, they preferred the flavor associated with physiological saline and strongly rejected the flavor associated with the food, even after a 22-h food deprivation period [80,[84][85][86].…”

“…Studies using this technique have demonstrated that the direct administration of complex food into the gastric cavity is a powerful way to establish flavor-conditioned aversions [66,80,[84][85][86]. Thus, when rats were subjected to a discriminative flavor learning task using whole milk as visceral stimulus, they preferred the flavor associated with physiological saline and strongly rejected the flavor associated with the food, even after a 22-h food deprivation period [80,[84][85][86]. Similar results were observed with intraintestinal feeding, finding that association of the intraduodenal administration of fats or glucose with the oral intake of saccharose or water produced a strong rejection of both in subsequent presentations [66,80,81,[86][87][88].…”

“…We have also used other procedures to explore the involvement of the LPBe in rewarding processes, including the induction of taste and place preferences by electrical stimulation of this subnucleus [135]. In addition, large lesions of the LPB, including the external subnucleus, appear to reverse aversive effects of the intragastric administration of natural, nonpredigested nutrients, avoiding rejection of the associated taste stimulus and appearing to induce a flavor preference (versus water) in late trials of the task [85].…”

Effects of intragastric administration of predigested nutrients on food intake, body weight and taste acceptability: Potential relevance of the cephalic/neural phase of digestion

“…However, these positive effects of the i.g. administration of nutrients are not observed in animals when natural, non-predigested foods are used (Deutsch et al 1976;Puerto et al 1976b;Zafra 2000Zafra , 2005.…”