BIOL 1F25 Lecture Notes - Lecture 13: Operant Conditioning, Dynorphin, Cyclic Adenosine Monophosphate
11 Jun 2015
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Document Summary
Synaptic vesicles containing chemicals (neurotransmitters) fuse with membrane and release chemicals. Chemicals move across synaptic cleft and bind to receptors on receiving cell, message is transferred. Dopamine transporter and cocaine: dopamine is normally recycled into pre-synaptic neuron, occurs via a dopamine transporter molecule on surface of pre-synaptic cell, cocaine attaches to transporter and blocks it. 1: more dopaminergic signalling at receiving neuron (post-synaptic cell) Reward pathways: mesolimbic dopamine pathway called the medial forebrain bundle. In the last 30 years: identi cation of molecular targets for most drugs of abuse. Brain opposes changes occurring during brain use: less dopamine release from pre-synaptic cell, post-synaptic receptors are down-regulated (reduced in number) When cocaine is absent from the brain : less dopamine released to activate pathway, less receptors to receive dopamine message. Chronic administration of cocaine up regulates camp pathway in the nac and activates creb. Produces decreased sensitivity to rewarding effects of subsequent drug exposure (tolerance)
