Biomaterial Database

Blockade of muscarinic acetylcholine receptors in the ventral tegmental area disrupts food-related learning in rats. 2006

Ruth Sharf, and Robert Ranaldi

Department of Psychology, Queens College, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA. rsharf1@yahoo.com

BACKGROUND Stimulation of ventral tegmental area (VTA) muscarinic acetylcholine receptors (mAChRs) is implicated in feeding. OBJECTIVE To investigate the effects of mAChR blockade in the VTA on food-related learning. METHODS In experiment 1, rats (N=12) were placed in chambers containing food and received microinjections of 0 or 5 microg/0.5 microl scopolamine prior to the first four feeding sessions and the alternate dose prior to the tenth feeding session. In experiment 2 (N=9), the effects of daily microinjections of scopolamine on lever pressing under a progressive ratio schedule of food reinforcement were tested. In experiment 3 (N=34), the effects of daily microinjections of scopolamine on lever pressing maintained by conditioned reward were investigated. RESULTS In experiment 1, all rats demonstrated low consumption during session 1. However, pellet consumption for rats initially pretreated with the 0-microg dose rose to and stayed at maximal levels for the remaining sessions, even when pretreated with the 5-microg dose during the tenth session. Pellet consumption for rats initially pretreated with the 5-microg dose remained low, even for the first two sessions following the cessation of scopolamine pretreatment, and gradually rose to maximal levels by the eighth session. In experiment 2, scopolamine significantly decreased break points. In experiment 3, scopolamine failed to significantly decrease responding specifically on the lever producing the conditioned reward. CONCLUSIONS Altogether, these data suggest that VTA mAChR stimulation is involved in feeding and food-related learning but may not be involved in responding maintained by conditioned reward.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011976	Receptors, Muscarinic	One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.	Muscarinic Acetylcholine Receptors,Muscarinic Receptors,Muscarinic Acetylcholine Receptor,Muscarinic Receptor,Acetylcholine Receptor, Muscarinic,Acetylcholine Receptors, Muscarinic,Receptor, Muscarinic,Receptor, Muscarinic Acetylcholine,Receptors, Muscarinic Acetylcholine
D012055	Reinforcement Schedule	A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent.	Reinforcement Schedules,Schedule, Reinforcement,Schedules, Reinforcement
D003213	Conditioning, Psychological	Simple form of learning involving the formation, strengthening, or weakening of an association between a stimulus and a response.	Conditioning, Psychology,Psychological Conditioning,Social Learning Theory,Social Learning Theories,Theory, Social Learning
D003214	Conditioning, Classical	Learning that takes place when a conditioned stimulus is paired with an unconditioned stimulus.	Reflex, Conditioned,Classical Conditioning,Classical Conditionings,Conditioned Reflex,Conditionings, Classical
D003216	Conditioning, Operant	Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.	Instrumental Learning,Learning, Instrumental,Operant Conditioning,Conditionings, Operant,Instrumental Learnings,Learnings, Instrumental,Operant Conditionings
D004435	Eating	The consumption of edible substances.	Dietary Intake,Feed Intake,Food Intake,Macronutrient Intake,Micronutrient Intake,Nutrient Intake,Nutritional Intake,Ingestion,Dietary Intakes,Feed Intakes,Intake, Dietary,Intake, Feed,Intake, Food,Intake, Macronutrient,Intake, Micronutrient,Intake, Nutrient,Intake, Nutritional,Macronutrient Intakes,Micronutrient Intakes,Nutrient Intakes,Nutritional Intakes
D005247	Feeding Behavior	Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.	Dietary Habits,Eating Behavior,Faith-based Dietary Restrictions,Feeding Patterns,Feeding-Related Behavior,Food Habits,Diet Habits,Eating Habits,Behavior, Eating,Behavior, Feeding,Behavior, Feeding-Related,Behaviors, Eating,Behaviors, Feeding,Behaviors, Feeding-Related,Diet Habit,Dietary Habit,Dietary Restriction, Faith-based,Dietary Restrictions, Faith-based,Eating Behaviors,Eating Habit,Faith based Dietary Restrictions,Faith-based Dietary Restriction,Feeding Behaviors,Feeding Pattern,Feeding Related Behavior,Feeding-Related Behaviors,Food Habit,Habit, Diet,Habit, Dietary,Habit, Eating,Habit, Food,Habits, Diet,Pattern, Feeding,Patterns, Feeding,Restrictions, Faith-based Dietary
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012201	Reward	An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.	Rewards