Autonomic and NMJ pharmacology Flashcards
what neurotransmitter acts on what type of receptor in the somatic nervous system?
Acetylcholine acts on nicotinic receptors.
what neurotransmitter acts on what kind of receptor in the sympathetic autonomic nervous system?
Acetylcholine acts on nicotinic receptors at the ganglion then noradrenline acts on alpha or beta receptors. (adrenaline or noradrenaline can also be secreted from the adrenal gland)
what neurotransmitter acts on what type of receptor in the parasympathetic autonomic nervous system?
acetylcholine acts on nicotinic receptors at the ganglion and muscarinic receptors.
what type of receptors are nicotinic?
ionotropic
what type of receptors are muscarinic?
metabotropic (split into m1,2 and 3 based on what g-protein they are coupled to)
are adrenergic receptors metabotropic or ionotropic?
metabotropic (again, can be split into sub types partly based on what g protein they are coupled to and what 2nd messengers get regulated)
what are the steps in synaptic transmission?
synthesis and packaging of neurotransmitter
action potential “invades” presynaptic terminal
opens voltage gated Ca2+ channels
causes calcium dependent exocytosis
transmitter diffuses across synaptic cleft and binds to ionotropic or metabotropic receptors to evoke postsynaptic response.
presynaptic autoreceptors prevent further transmitter release
transmitter usually inactivated by uptake into glia or neurones, where it is then metabolised.
how could you stop synapses in the NMJ from working effectively?
inhibit choline transporter block voltage gated caclium channels block vesicle fusion non depolarising nicotinic receptor blockers depolarising nicotinic receptor blockers
how could you make synapses in the NMJ work more effectively?
trigger release of MORE calcium; results in more ACh being released.
use anticholinesterases so that acetylcholine stays in the synaptic cleft for longer.
what is the effect of a muscarinic agonist?
mimics the effect of the parasympathetic nervous system.
what is the effect of a muscarinic antagonist?
blocks effects of the parasympathetic system
how could you make a drug that acts on muscarinic receptors act selectively as opposed to mimicking/blocking all the effects of the parasympathetic nervous system?
deliver the drug directly to the site of action.
how can you reduce the effectiveness of the postganglionic synaptic effect in the sympathetic nervous system?
block enzymes that produce NA
activate inhibitory presynaptic autoreceptors
block alpha or beta postsynaptic receptors
what amino acid is the precursor for noradrenaline?
tyrosine
what 3 enzymes catalyse the conversion of tyrosine into NA?
tyrosine hydroxylase, DOPA carboxylase and dopamine hydroxylase
