Infralimbic EphB2 Modulates Fear Extinction in Adolescent Rats.
Adolescent rats are prone to impaired fear extinction, suggesting that mechanistic differences in extinction could exist in adolescent and adult rats. Since the infralimbic cortex (IL) is critical for fear extinction, we used PCR array technology to identify gene expression changes in IL induced by fear extinction in adolescent rats. Interestingly, the ephrin type B receptor 2 (EphB2), a tyrosine kinase receptor associated with synaptic development, was downregulated in IL after fear extinction. Consistent with the PCR array results, EphB2 levels of mRNA and protein were reduced in IL after fear extinction compared with fear conditioning, suggesting that EphB2 signaling in IL regulates fear extinction memory in adolescents. Finally, reducing EphB2 synthesis in IL with shRNA accelerated fear extinction learning in adolescent rats, but not in adult rats. These findings identify EphB2 in IL as a key regulator of fear extinction during adolescence, perhaps due to the increase in synaptic remodeling occurring during this developmental phase.
Department of Basic Sciences, Ponce Health Sciences University-School of Medicine/Ponce Research Institute, Ponce, Puerto Rico 00732, and.
Emmanuel
E
Cruz
Department of Basic Sciences, Ponce Health Sciences University-School of Medicine/Ponce Research Institute, Ponce, Puerto Rico 00732, and.
Omar
O
Soler-Cedeño
Department of Biology, Pontifical Catholic University of Puerto Rico, Ponce, Puerto Rico 00717.
Geovanny
G
Negrón
Department of Basic Sciences, Ponce Health Sciences University-School of Medicine/Ponce Research Institute, Ponce, Puerto Rico 00732, and.
Marangelie
M
Criado-Marrero
Department of Biology, Pontifical Catholic University of Puerto Rico, Ponce, Puerto Rico 00717.
Gladys
G
Chompré
Department of Basic Sciences, Ponce Health Sciences University-School of Medicine/Ponce Research Institute, Ponce, Puerto Rico 00732, and jporter@psm.edu.
James T
JT
Porter
D000679:Amygdala / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D005108:Extinction, Psychological; D005239:Fear; D008297:Male; D017397:Prefrontal Cortex / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D036183:Receptor, EphB2 / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D036183:Receptor, EphB2
EphB2; adolescent; amygdala; extinction; medial prefrontal cortex