[대학원 생명과학과 세미나 안내]
연사 : 정지혜 교수(건국대 생명과학특성학부)
연제 : Meta-plasticity of disappointed synapses
일시 : 2017년 11월 24일 (금) 오후 5시
장소 : 하나과학관 A동 B131호
초청교수 : 백자현 교수
Abstract
Stress exposure is known to cause depression in human patients and animal models, although the responsible cellular mechanisms remain to be elaborated. The lateral habenula (LHb) is a small part of the epithalamus that projects to monoamine centers in the brain. Previously, neurotransmission onto the LHb was shown to be abnormally potentiated in animal models of depression. However, synaptic plasticity in this brain area and the effect of stressor exposure on synaptic plasticity of the LHb have not been investigated. We explored whether the LHb undergoes dynamic changes in synaptic efficacy or not. First, we observed that both long-term potentiation (LTP) and long-term depression (LTD) occurs in LHb neurons obtained from naïve animals. Surprisingly, exposure to acute stressors completely masked the induction of a certain type of LTD, while greatly facilitating LTP induction in the LHb. Stress exposure selectively increased the number of neurons expressing pCREB in the LHb, suggesting that the threshold for LTP induction has lowered in animal models of depression. Pharmacological activation of cannabinoid receptor 1 (CB1R) or blockade of aCaMKII successfully restored LTD in the LHb in an animal model of depression. I will discuss our observations revealing previously unknown forms of synaptic plasticity in the epithalamus and stress-induced shift of the bi-directional synaptic plasticity, i.e. metaplasticity in the LHb in animal models of depression.