Neuromuscular Junction Flashcards
Exocytosis of vesicle containing neurotransmitters is triggered by
Calcium influx
Amine neurotransmitters include
Acetylcholine, noradrenaline, Adrenaline and serotonin (5HT)
Amino acid neurotransmitters include
glutamate, GABA
Sympathetic postganglionic nerves use which neurotransmitter
noradrenaline
parasympathetic post ganglionic nerves use which neurotransmitter
Acetylcholine
Preganglionic neurons use which neurotransmitters
Acetylcholine
which post ganglionic axons are longer, sympathetic or parasympathetic?
sympathetic
noradrenaline, adrenaline and dopamine are all derived from
tyrosine
Alpha 1 adrenergic receptors cause
smooth muscle contraction in vascular, genitourinary and eye (plus gluconeogenesis in liver)
beta 1 adregergic receptors cause
increased rate and force of heart
Sympathetic nervous system effects are
pupil dilation, increased heart rate,dilate bronchial smooth muscle, decreased gut motility, increased sweating, constrict blood vessels (mostly), dilates skeletal muscle blood vessels
ACh receptors can be
muscarinic or nicotinic
Nicotinic receptors are found
on postganglionic sympathetic and parasympathetic nerves with cell bodies in CNS (ganglion’s and adrenal medulla)
muscarinic receptors are found
at effector organ
nicotinic (neuronal type) receptors are
ligand gated ion chanels in ganglion or adrenal medulla
muscarinic receptors are
G protein coupled receptors which are not susceptible to depolarisation blockade
the muscarinic receptors mostly within the CNS are
M1, M4 and M5
the muscarinic receptors within the peripheral tissues are
M2, M3
M1 receptors are responsible for
salivation, gastric acid secretion and increase CNS actions
M2 receptors have
cardiac inhibitory effects
M3 receptors are
smooth muscle contractors in GIT, vasodilation (via NO) and glandular secretion (sweating)
M4 and M5 receptors are
mostly in CNS and may be implicated by nuerological conditions such at Alzheimers, Parkinson’s etc.
Parasympathetic effects are
miosis, increased salivation, decreased HR, bronchoconstriction, peristalisus, bile release, bladder contraction
Adrenoreceptors are
G coupled
alpha 2 adrenoreceptors cause
decreased transmitter release at presynaptic nerve terminals
beta 2 adrenoreceptors
vascular smooth muscle relaxation, uterine smooth muscle relaxation and bronchial smooth muscle contraction (and glycogenolysis in liver)
beta 3 adrenoreceptors are
lipolysis in fat, GI smooth muscle relaxation
cholinergic receptors on skeletal muscle are
nicotinic
serotonin (5HT ) has what effects
GIT motility, platelet aggregation, emesis, sleep-wake cycle, appetite, depression
nitric oxide, which is a lipid soluble gas synthesised on demand, associated with
vessel dilation
AS ACh constantly associates and dissociated from nAChR what happens
AChE is contacted and breaks dwon ACh
