neuro - unit 2: neurotransmitters

neurotransmitter

molecule that is localized, synthesized, and released by neurons

dale's principle

a neuron preforms the same chemical action at all of its synaptic connections to other cells, regardless of the identity of the target cell

types of neurotransmitter receptors

ionotropic and metabotopic

ionotropic receptors

transmitter gated ion channel receptors

Metanotropic receptors (GPCRs)

-G Protein Coupled Receptors: membrane proteins involved in signal transduction

-binding of an intracellular G protein turns on an active site to affect an intracellular pathway

• second messenger

Acetylcholine (ACh)

NT of neuromuscular junctions

alpha-bungarotoxin

blocks neuromuscular transmission as the venom binds to the Nicotine ACh receptors causing paralysis of respiratory muscles

(in post-synaptic cell)

epsp

Excitatory postsynaptic potential; a slight depolarization of a postsynaptic cell pushing it closer to the threshold for an AP

makes cell more positive as Na+ flows into the cell

ipsp

Inhibitory postsynaptic potential; a slight hyperpolarization of the postysynaptic cell, moving the membrane potential of that cell further from threshold.

makes cell more negative as Cl- flows in

shunting inhibition

inhibiting current flow from soma to axon hillock

all neurotransmitters

acetocholine, epinephrine, norephinephrine, dopamine, seratonin, opiods, glutamate, glycine, GABA

acetocholine (Ach)

Acetyl CoA + Choline is synthasized by ChAT into Ach (+CoA) which is then degraded by AchE into Acedic Acid + Choline

black spider venom

makes pores in terminals, causing an influx of Ca2+ in motor neurons => uncontrolled release of NT's which causes contractions in the body

myathenia gravis

autoimmune disease in which antibodies attack Ach Receptors (on post-synaptic)

s/s: drooping of upper eyelid and double vision due to weakness in extraocular muscles, difficulty chewing and swallowing, weakness of extremities, and general decrease in muscular endurance;

manage: drugs that inhibit breakdown of acetylcholine, corticosteroids to suppress immune system

botulinum toxic (botox)

bacteria that prevent the release of Ach (presynaptic cell)

doesnt let vessicles release NT => prevents muscles from moving since no signal is sent

catecholamines

found in regions of nervous system involved in the regulation of movement, mood, attention, and visceral functions (dopamine, norepinephrine, epinephrine)

indolamines

involved in mood, eating, sleeping, and arousal (serotonin)

SSRIs

Selective serotonin reuptake inhibitors block the reuptake of seratonin which increases the amount present in the synapse & magnifies its effects

LSD

seratonin receptor agonist

Ecstasy

both stimulates release & inhibits uptake of 5HT

dopamine

involved in attention, learning, addiction, reward pathways

seratonin

involved in mood, eating, sleeping & arousal

glutamate

main excitatory NT of the nervous system

GABA

often inhibitory

Glycine

inhibitory

neuropeptides

large signaling molecules (opioids)

used for pain management of acute pain but high risk of substance abuse

nicotinic receptor

excitatory acetylcholine receptor protein that is an ionotropic

agonist: nicotine

antagonist: curare

muscarinic receptor

inhibitory or excitatory receptor protein that is a metabotropic receptor

agonist: atropine

antagonist: muscarine