Lecture 7 - The ANS Flashcards
(19 cards)
Are nicotinic acetyl choline receptors ligand gated ion channels or g-protein coupled receptors?
Ligand gated ion channels
What does the autonomic nervous system control?
Heart rate Blood pressure Gi motility Iris motility Iris diameter
Are muscarinic acetyl choline receptors ligand gated ion channels or g-protein coupled receptors?
G-protein coupled receptors
What system do sweat glands use?
They are part of the sympathetic nervous system however have there final synapse as a muscarinic ACh receptor
What other transmitters are found in the ANS?
Non-adrenergic, non cholinergic transmitters (NANC)
E.g. ATP which is used in post ganglionic fibres innervating expulsion of semen
e.g. Nitric oxide and several neuropeptides
What is special about innervation to the adrenal gland?
It is one long neuron speeding up the response, which differentiates into secretory chromaffin cells.
Outline acetylcholine synthesis
Acetyl CoA + Choline –> Acetylcholine + Coenzyme A
Enzyme = choline acetyl transferase
Outline Acetylcholine degradation
Acetylcholine –> Acetate + Choline
Enzyme=Acetylcholinesterase
Outline noradrenaline synthesis
Tyrosine–>DOPA–>Dopamine–>Noradrenaline
Outline noradrenaline degradation
Noradrenaline degradation is a complex process. It can be take up into the presynaptic terminal and re synthesized by two forms of uptake:
Uptake 1- high affinity Low activity
Uptake 2- Low affinity High activity
The enzyme then used to degrade it can be monoamine oxidase or catechol-o-methyl transferase
What does an agonist do?
Produce a response
What does an antagonist do?
Prevent a response
What is an agonist of the nAChR?
Nicotine
What is an antagonist of nAChR?
Trimethaphan
What is an agonist of mAChR?
Pilocarpine
What is an antagonist of mAChR?
Homatropine
What is an agonist of alpha 1 adrenoceptors?
Phenylephrine
What is an antagonist of alpha 1 adrenoceptor?
Prazosin
What is acetylcholinesterase inhibited by?
Edrophonium
Physostigmine
