Drugs of Abuse: Neuronal Survival and Signaling

描述(由申请人提供)： 这项拟议研究的最广泛目标是描述伴随着电活动增加和减少而发生的突触信号的变化。长期接触滥用药物，如乙醇、巴比妥酸盐和苯二氮卓类药物，会导致电活动下调，最终导致神经元死亡。目标1的目的是确定这种神经元活动的减少是由于药物对钙电流的影响而导致神经递质释放减少，还是通过启动稳态机制而导致神经递质释放增加。突触信号的这种变化可能会减弱或加强滥用药物对神经元存活的影响。目标2的目的是确定用K去极化模拟增加的电活动对突触信号的影响。初步数据表明，去极化可以抑制谷氨酸能突触的发育，同时保持抑制电流不变。将进行实验，以区分突触前和突触后机制是否解释了K对兴奋电流的这种影响。AIM 1和AIM 2都将在海马微培养范例中利用全细胞膜片钳技术，这将有助于突触电生理学的检查。

DESCRIPTION (provided by applicant): The broadest objective of the proposed research is to characterize the changes in synaptic signaling that accompany increases and decrease in electrical activity. Chronic exposure to drugs of abuse such as ethanol, barbiturates, and benzodiazepines causes a downregulation in electrical activity, which ultimately leads to neuronal death. The goal of Aim 1 is to determine whether this decrease in neuronal activity results in reduced neurotransmitter release because of drug effects on Ca2+ currents, or in enhanced neurotransmitter release through initiation of homeostatic mechanisms. Such changes in synaptic signaling could either lessen or intensify the effects of drugs of abuse on neuronal survival. The goal of Aim 2 is to determine the effects on synaptic signaling caused by mimicking increased electrical activity with K+ depolarization. Preliminary data indicate that depolarization curtails development of glutamatergic synapses, while leaving inhibitory currents intact. Experiments will be conducted to distinguish whether a presynaptic and a postsynaptic mechanism accounts for this effect of K+ on excitatory currents. Both Aim 1 and Aim 2 will utilize whole-cell, patch-clamp techniques in a hippocampal microculture paradigm, which will facilitate examination of synaptic electrophysiology.