NROC69H3 Lecture Notes - Lecture 2: Gria2, Curare, Reuptake
Document Summary
Lead to the idea that 1 ach molecule 1 ach receptor idea turned out to be wrong: but. Amplitude of mepps could be manipulated by the administration of curare (nachr blocker) or acetylcholinesterase (breaks down ach) inotophoretic application of ach caused smooth, small depolarising responses. Mepp must reflect opening of many individual ach receptors, rather than the one. Delcastillo and katz (1954: under conditions of low extracellular ca2+, stimulation of the presynaptic motor neuron caused the magnitude of the end plate potential (epp) to fluctuate in a stepwise manner. Evoked epp amplitudes were: of the size of a mepp, sizes at integral multiples of minis, quantal hypothesis of neurotransmitter release. Neurotransmitters are released from the presynaptic terminal in discrete units / quanta. Mepp is response to a spontaneous release of a single quantum, and is thus a building block of epp. Epp is a response to some 100s of these quanta.