Psyc 181

Updated 2007-02-19 08:01

Midterm 2: LECTURE 5

Synapsessite of action of most psychoative drugs
Parts of SynapsesSoma, Axon, Dendrite, Synaptic vesicles, synaptic cleft, post synaptic, presynaptic, glia
Types of cell-cell junctionsTight (membranes fused), Gap (close juxtaposition, electrical synapse), Chemical (synaptic cleft, polarized)
Vesicle VarietiesSpherical agranular, spherical granular, reciprocal junction, flattened vesicles
Multiple Patterns of ConnectivityAxodendritic, Dendrodendritic, Axoaxonic, Axosomatic
Steps in synaptic transmissionSynthesis, Transport, Storage, Release, Inactivation
ReleaseExcitation-secretion coupling: Depolarization, Open voltage-gated Ca++ channels, Ca++ influx, Bind to Ca++ -calmodulin protein kinase, Phosphorylation of synapsin I, Movement of vesicles to release site, Exocytosis, Diffusion
InactivationReuptake (transporters), Enzymatic degradation (metabolism, excretion, cycling)
Nerotransmitters (2 TYPES)Classical (small water soluble molecules with amine, formed from dietary precursors) & Neuropeptides (protein synthesis)
Neurotransmitters (EXs)Phenylethylamines (DA, NE, E, tyramine), Indoleamines (5-HT, tryptamine, melatonin), Cholinergics, Amino Acids (glutamate, glycine, GABA), Neuropeptides (Enkephalins, substance P, neurotensin), Nonpeptide hormones (progesterone)
AutoreceptorsPresynaptic, Somatodendritic, Terminal, Release-Modulating, Synthesis-modulating, Impulse-modulating
Transductionprocess by which changes itself, letting something happen on inside of cell - purpose being to magnify the biological effect of drugs
Receptor Superfamilies1. Ligand-gated channels 2. G protein-coupled
Ligand-gated channels"RAPID" Binding site coupled into ion channel, Transmitter (or drug) gates the channel, ionotropic(rapidly unbind=closes channel) receptors
Examples of Ligand-gated ChannelsNicotinic acetylcholine receptor (coupled to sodium channel, drugs: nicotine, curare) & GABAa receptor (coupled to chloride channel, drugs: sedative-hypnotics)
G Protein-coupled receptorsreceptor coupled to G protein, G protein activates effector, metabotropic (big metabolic pathway) receptors
G protein-coupled classesG protein directly coupled to ion channel (effector is ion chennel) & G protein coupled to 2nd messenger system (effector is enzyme that promotes formation of intracellular "second messenger"
Exs of G protein-coupled rec.Cholinergic muscarinic, GABA b, 5-HT, Opioid, Dopamine, Norepinephrine
Second MessengersCalcium, cGMP, Phosphoinositides, cAMP(cyclic adenosine 3,5-monophosphate)
Protein PhosphorylationMAKING PROTEIN ACTIVE, changes structure/function of protein, consequence depends on function of protein
Second messengers & protein kinases have many targetsonce kinases are activated, it can effect all kinds of things, changes gene regulation and we can have more or less protein made
Gene RegulationSecond messengers can alter it.. Activate transcription factors, regulate transcription (enhance or supress), if enhance - new gene products
Phases of Gene RegulationInitial Phase (induction of immediate-early genes (IEGs), protein products initiate 2nd phase. Second Phase (induction of "late-onse genes", products that alter cellular function