TY - JOUR
T1 - Metabotropic glutamate receptor 5 in conditioned taste aversion learning
AU - Simonyi, A.
AU - Serfozo, P.
AU - Parker, K. E.
AU - Ramsey, A. K.
AU - Schachtman, T. R.
N1 - Funding Information:
Supported in part by R03 MH64486-01A1 from NIH. We thank Dr. Phullara Shelat for her assistance.
PY - 2009/10
Y1 - 2009/10
N2 - In conditioned taste aversion (CTA), animals learn to avoid a flavored solution (conditioned stimulus, CS) previously paired with internal malaise (unconditioned stimulus, US). Metabotropic glutamate receptor 5 (mGlu5) has been implicated in learning and memory processes and is necessary for CTA. In the present study, local microinjections of a mGlu5-selective antagonist, 3-[2-methyl-1,3-thiazol-4yl)ethynyl]pyridine (MTEP, 0, 1 or 5 μg) into the insular cortex and basolateral amygdala were used in male, Sprague-Dawley rats to examine the role of mGlu5 receptors in the encoding of taste memory. MTEP was infused 20 min before saccharin intake during CTA conditioning. MTEP injection into the basolateral amygdala resulted in robust CTA, similar to the vehicle-treated animals but slowed extinction; that is, MTEP enhanced CTA. MTEP injection into the insular cortex resulted in an increased saccharin intake on the conditioning trial, which potentially influenced the performance on the test trials; MTEP had no effect on CTA learning when controlled access to saccharin was used on the conditioning trial. These results indicate that mGlu5 receptors are involved in taste memories in a region-specific manner.
AB - In conditioned taste aversion (CTA), animals learn to avoid a flavored solution (conditioned stimulus, CS) previously paired with internal malaise (unconditioned stimulus, US). Metabotropic glutamate receptor 5 (mGlu5) has been implicated in learning and memory processes and is necessary for CTA. In the present study, local microinjections of a mGlu5-selective antagonist, 3-[2-methyl-1,3-thiazol-4yl)ethynyl]pyridine (MTEP, 0, 1 or 5 μg) into the insular cortex and basolateral amygdala were used in male, Sprague-Dawley rats to examine the role of mGlu5 receptors in the encoding of taste memory. MTEP was infused 20 min before saccharin intake during CTA conditioning. MTEP injection into the basolateral amygdala resulted in robust CTA, similar to the vehicle-treated animals but slowed extinction; that is, MTEP enhanced CTA. MTEP injection into the insular cortex resulted in an increased saccharin intake on the conditioning trial, which potentially influenced the performance on the test trials; MTEP had no effect on CTA learning when controlled access to saccharin was used on the conditioning trial. These results indicate that mGlu5 receptors are involved in taste memories in a region-specific manner.
KW - Acquisition
KW - Amygdala
KW - Conditioned taste aversion
KW - Insular cortex
KW - Metabotropic glutamate receptor 5
UR - http://www.scopus.com/inward/record.url?scp=69249210980&partnerID=8YFLogxK
U2 - 10.1016/j.nlm.2009.05.002
DO - 10.1016/j.nlm.2009.05.002
M3 - Article
C2 - 19439188
AN - SCOPUS:69249210980
SN - 1074-7427
VL - 92
SP - 460
EP - 463
JO - Neurobiology of Learning and Memory
JF - Neurobiology of Learning and Memory
IS - 3
ER -