Lecture 2: Chemical synapses

Resting membrane potential

dependent on changes in K+, not Na+ (leak K+ channels)

Action potential spike height

dependent on changes in Na+, not K+

Action potential duration

dependent on changes in K+, not Na+ (VG K+ channels)

Synapse

a cell to cell junction (between neurons or a neuron and a muscle)

Excitatory synapse

gets more positive (depolarize)

Inhibitory synapse

gets more negative (repolarize)

Ionotropic receptor

is a receptor and a channel; ligand binds, channel opens allowing ions to flow

Metabotropic receptors

is a receptor and binding of a ligand begins some kind of 2nd messenger cascade

Selective serotonin reuptake inhibitors (SSRI)

used when there is deficiency in serotonin; block the reuptake of protein, serotonin remains in cleft = constant excitation

Anti-anxiety medication

not enough inhibition at GABA synapses; medication are GABA agonist, they promote more GABA transmission thus the post-synapse is more negative = inhibition

GABA

has a negative charge; increase uptake of GABA results in hyperpolarization l

Local anesthetics; procaine and lidocane

blocks VG Na+ channels from opening