BIOL 460 1nd Edition Lecture 5 Outline of Last Lecture I Sympathetic division a Sympathoadrenal system II Parasympathetic division III Autonomic Function IV NTMs in ANS a Ach i Cholinergic neurons ii Cholinergic receptors Outline of Current Lecture I NTM in ANS continued a Norepinephrine i Adrenergic neurons ii Adrenergic receptors 1 Alpha 1 2 Alpha 2 3 Beta b Nonadrenergic noncholinergic fibers Current Lecture 1 Norepinephrine a Adrenergic neurons i All adrenergic receptors are g protein linked ii Norepinephrine raises heart rate EPSP relaxes smooth muscle in bronchi IPSP iii Most sympathetic post ganglionic neurons are adrenergic iv Exception are axons helping visceral effector in somatic parts of body Ach b Adrenergic receptors i Alpha 1 Alpha 1 vascular smooth muscle in skin and viscera generate EPSPSs causing vasoconstriction a Figure 11 9 pathway for alpha 1 receptors i Bond to norepinephrine These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute ii Phospholipase C Ca2 2nd messenger system iii G protein turn on phospholipase C enzyme iv Phospholipase C in plasma membrane takes phospholipid from PM and breaks phosphate off ester bond v Produces 2 molecules that can be 2nd messengers 1 Inositol triphosphate IP3 polar hydrophilic 2 Diacyl glycerol DAG hydrophobic restricted to PM vi IP3 moves through cytoplasm to ER pump constantly pumps Ca2 into ER vii IP3 bonds to Ca2 ligand gated channel on ER membrane viii Channel opens Ca2 diffuses into cytoplasm and binds to calmodulin gives Ca2 Calmodulin complex which activates protein kinases causing the physiological effect ix Turning off 1 Ca2 pumped back into ER 2 Protein phosphatases reverse protein kinase effects 3 IP3 destroyed by an enzyme 4 G protein turns itself off 5 NTM destroyed 2 Alpha 2 terminal boutons of sympathetic post ganglionic neurons negative feedback system used to monitor sympathetic division a Use andenylate cyclase cAMP pathway b On terminal boutons of some sympathetic post ganglionic neurons c Norepinephrine released d Binds to A1 B1 B2 on post synaptic cell e Alpha 2 on terminal bouton f Some norepinephrine bond to alpha 2 receptor functions like beta receptors andenylate cyclase cAMP STP g Result is to open K ligand gated channel h K diffuses out creating IPSP i Interferes with opening of Ca2 VGC on terminal bouton j Decreases release of norepinephrine keeping sympathetic nervous system in check k They have found an A2 agonist captapres or clonidinelowers blood pressure by decreasing sympathetic response ii Beta 1 Beta 1 on heart generates EPSP heart rate up stronger contraction 2 Beta 2 smooth muscle SM of bronchioles relaxes bronchodilation nonvascular SM of viscera IPSPS 3 B blockers designed to block B1 which lowers heart rate 4 B adrenergic receptor pathway a Andenylate cyclase cAMP 2nd messenger system b Norepinephrine binds c G protein does its thing d Turns on andenylate cyclase e ATP hydrolyze cAMP and pyrophosphate f Protein subunits are dimers i Catalytic subunit bind to cause IPSP ii Inhibitory subunit greater affinity to catalytic subunit iii In absence of cAMP inhibitory subunit will bind to catalytic subunit preventing action g Turn off i cAMP broken down by phosphodiesterase ii protein kinases reversed by phosphatases 5 beta blockers a original used for hypertension b propranolol i blocks B1 and B2 ii b antagonist blocked B2 not good c atenolol i B1 antagonist ii Decreased blood pressure but no bronchoconstriction 6 Asthma a Inhaler used to contain epinephrine b Caused bronchodilation and increased heart rate blood pressure c Also bonded to alpha 1 and alpha 2 d Now use terbutaline i Selective b2 agonist ii Causes bronchodilation iii Side effect constipation 2 Nonadrenergic noncholinergic Fibers a Fibers can release several NTM b One is NO
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