BIOM 3090 Lecture Notes - Lecture 11: Muscarinic Acetylcholine Receptor M3, Muscarinic Acetylcholine Receptor, Somatic Nervous System
9 Jun 2018
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Communication in ANS
- autonomic nerves classified based on primary
neurotransmitters
o Acetylcholine (ACh)
o Norepinephrine (NE)
- Cholinergic Neurons = release ACh
- Noradrenergic (adrenergic) neurons = release NE
(Noradrenaline) or EP (adrenaline = epinephrine)
Autonomic receptors
- Cholinergic
o Muscarinic (M1, M2, M3, M4, M5) → m2 and M3 most imp
▪ Organs innervated by PSNS (M2, M3)
▪ Endothelial cells (M3 and M5) (most M3)
▪ Sweat glands innervated by cholinergic SNS fibres (M3)
▪ Some ganglia (M1)
▪ CNS (all sub-types)
▪ M4 not yet been identified!
o Nicotinic (Nn Nm)
▪ Nn found in all neurons in ganglia
(PSNS and SNS), drugs will activated
both pathways
▪ Nm found on skeletal muscle
(somatic nervous system)
- Adrenergic
o Found in organs innervated by SNS and in
CNS
o Location and subtype determine tissue
response
▪ Alpha (1, 2): activated by NE and EP
▪ Beta (1, 2, 3): Activation of 2 EP>>>NE (2 responsive to
EP but not NE)
Tonic level of activity in ANS
- most tissues: PSNS and SNS = physiological antagonists
- autonomic drugs, stress, environmental input → alteration in the balance of
neurotransmission
o e.g. Heart – activation of M2 lowers HR, fight or flight stimulates heart
and faster strength of receptor, circulation
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Autonomic nerves classified based on primary neurotransmitters: acetylcholine (ach, norepinephrine (ne) Noradrenergic (adrenergic) neurons = release ne (noradrenaline) or ep (adrenaline = epinephrine) Adrenergic: found in organs innervated by sns and in. Cns: location and subtype determine tissue response, alpha ( 1, 2): activated by ne and ep, beta ( 1, 2, 3): activation of 2 ep>>>ne ( 2 responsive to. Most tissues: psns and sns = physiological antagonists. Autonomic drugs, stress, environmental input alteration in the balance of neurotransmission: e. g. heart activation of m2 lowers hr, fight or flight stimulates heart and faster strength of receptor, circulation. Cholinergic transmission synthesized by the enzyme choline acetyltransferase (chat) Acetylcholine (ach) activates: muscarinic receptors: m1,m2, m3, Increase ip3 dag = stimulatory and decrease camp = inhibitory: nicotinic: nn, nm. All 5 muscarinic receptor subtypes in cns. No psns input in blood vessels but cholinergic receptors are present on endothelial cells that line the blood vessels (direct agonists relax vascular smooth muscle)
