lecture_notes_07_(ta)

lecture_notes_07_(ta) - Lecture 7 Synaptic Transmission...

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Lecture 7: Synaptic Transmission II (TA NOTES IN RED . P LEASE NOTE THAT I AM USING AN OLD VERSION OF THE LECTURE NOTES . FIGURE AND PAGE NUMBERS REFER TO THE FIFTH E DITION OF OUR TEXT …) Transmitter removal - several mechanisms are present in chemical synapses to remove transmitter that has been released into the synaptic cleft. The transmitter molecules can be degraded by enzymes present in the synaptic cleft, transported back into the presynaptic neuron by active transport, or can diffuse out of the cleft. Each of these mechanisms reduces the duration of action of the transmitter and insures that its action will be brief. ( SEE PREVIOUS LECTURE FOR TRANSMITTER REMOVAL NOTES ) Drug actions - many drugs exert their actions on the nervous system by influencing one or more of the processes listed above. These actions are usually either antagonistic or facilitory. transmitter release - tetanus toxin degrades vesicle fusion transmitter uptake - Cocaine blocks the reuptake of Dopamine SSRIs (selective seratonin reuptake inhibitor) transmitter removal - many insecticides block the degradation of ACh EPSP - Curare blocks the postsynaptic action of ACh at the neuromuscular junction IPSP - Valium enhances the postsynaptic action of GABA THC – is an agonist for the endogenous cannabanoid receptor ( HUH , WHAT WERE WE TALKING ABOUT ?) 2nd messenger - Caffeine enhances the action of cAMP at adrenergic synapses ( WITH REGARD TO N EUROTRANSMITTERS : - AN ‘A GONIST INCREASES THE EFFECTS OF A NEUROTRANSMITTER . IS MOST OFTEN A CHEMICAL WHICH CAN MIMIC THE EFFECT OF A NEUROTRANSMITTER . F OR INSTANCE , NICOTINE IS AN AGONIST FOR ACETYLCHOLINE ; IT FITS INTO THE AC H RECEPTOR AND ACTIVATES IT . T ECHNICALLY , THOUGH , AN AGONIST IS A CHEMICAL WHICH INCREASES THE ACTIVITY OF A RECEPTOR . -A
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lecture_notes_07_(ta) - Lecture 7 Synaptic Transmission...

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