Here is another set of Q and As you might find useful Zoo Psych Neuro 523 Problem Set 8 answers 2016 1 Define briefly Nicotinic vs muscarinic acetylcholine receptor Nicotinic receptors are ligand gated channels that are gated by acetylcholine They have 5 subunits and each has 4 transmembrane domains one of which M2 is responsible for gating It rotates 15 about its axis to produce channel opening Muscarinic receptors are 7 transmembrane domain G proteinlinked receptors Facilitation We haven t covered this yet wait until next week Reserpine Blocks uptake of dopamine or norepinephrine into synaptic vesicles in adrenergic neurons No release possible because vesicles become empty of transmitter No synthesis of NE because DBH is inside vesicle Ruthenium Red Causes release of calcium ions stored in mitochondria thus increasing the intracellular concentration of calcium ions Leads to increase in spontaneous mepp frequency 2 In what ways do the two different species of membrane transporter molecules that are important in cholinergic terminals resemble each other The two transporters are the choline transporter in the presynaptic membrane and the ACh transporter in the synaptic vesicle The choline transporter uses the Na ion gradient as its energy source and the ACh transporter uses the proton gradient set up by the proton transporter in the SV that acidifies the lumen of the vesicle to pH 5 5 The choline transporter is blocked by HC3 and the ACh transporter by vesamicol 3 What contributions did the study of epinephrine release from the adrenal medulla make to the understanding of the mechanisms of secretion It was shown that the granules vesicles containing epinephrine also contained ATP chromogranin A and a soluble form of dopamine betahydroxylase When release was stimulated the contents were released in the same ratio that they were present in the granules which strongly supported the vesicle hypothesis that to get release compounds are packed into vesicle and undergo exocytosis 4 How would you measure quantal content and quantal size at a neuromuscular junction If you selectively opened non voltage sensitive K channels in the muscle cell membrane with a newly discovered toxin from the Loch Mendota Monster how would this affect quantal content and quantal size Please explain your answer briefly Quantal content is the average number of quanta released per stimulus i e the average number of vesicles that fuse with the presynaptic membrane each time the nerve is stimulated It can be measured in two ways either by adding up the values of the synaptic potentials in a series of trials dividing by the number of trials to give the average response and then dividing by the average size of the spontaneous mepp to give the average number of quanta in each response The alternative is to use the first term of the Poisson distribution p 0 which is e m so ln p0 m Quantal size is the average amplitude of the mepp If the K conductance of muscle is increased by the toxin this would decrease the input resistance of the postsynaptic cell so the quantal size would decrease but the quantal content a presynaptic phenomenon would not change 5 Describe briefly the mechanisms that increase the diversity of neuropeptides that can be produced by an organism There is a multiplicity of genes that encode peptide precursor proteins Precursor proteins can be cleaved in different ways in different cells differential processing In some cells the RNA is spliced differently alternative splicing so that the exons are shuffled into different mature mRNAs