Sphincter pupillae contraction via Ach on M3 R.contraction via M3 to make globular lens (near vision) + outflow (stimulated by pilocarpine).relaxation via b2 to flatten lens (far vision) + secretion aqueous humour from ciliary epithelium (blocked via topical timolol).a2 = Reduced aqueous humour secretion (brimonidine).Dilator pupillae contraction via a1 = open pupil (mydriasis) + outflow of aqueous humour.Levodopa (PD, hyperprolactinaemia) Fenoldopam (severe HTN)Īpocrine sweat glands (axillary/ perineal regions) – adrenergic sympathetic innervation-> NEĮccrine sweat glands (throughout body) – thermoregulatory function: short preganglionic cholinergic fibre (thoracolumbar region) release Ach on nicotinic R of long post ganglionic neuron-> postganglionic neuron release Ach on muscarinic R of effector organ Eye Smooth muscle – vasodilation renal, splanchnic, coronary, cerebral vessels Timolol (glaucoma) Decrease production of aqueous humour and reduce IOP Butoxamine (b2 > b1)Īdipose – lipolysis Detrusor muscle – relax Isoprenaline(b1=b2 >a) Positive ino/chronotropy Potent vasodilator Net effect = increase systolic, decrease diastolic thus decrease MAP Salbutamol (b2>b1>a) Relaxes smooth muscle (vasodilation, decreased motility in G/ GU, ciliary muscle for far vision) Lungs – bronchodilation, inhibition mast cells Tx IHD to decrease cardiac oxygen demand, arrhythmias, CCF, hyperthyroidism Propranolol, timolol (non-selective, b1=b2) Metoprolol, atenolol, esmolol, nebivolol (selective, b1 > b2) Labetalol, carvedilol (mixed, b1= b2, > a1) Heart – increase HR (inotropy) + contractility (chronotropy) + conduction velocity through nodes (dromotropy)Įpinephrine (a1=a2, b1=b2) Initial rise in SBP due to b1 then fall due to b2 Isoprenaline (b1=b2 >a) Dobutamine (b1>b2>a) positive ino/chronotrope activation a1 thus TPR does not fall significantly used in cardiac stress test Gs protein = Increased cAMP and PKA activity Stimulated by DA at low doses. Raises BP, HR Tx male erectile dysfunction Yohimbine (a2 > a1) increased SNS activity and NE release Sedation in ICU/ anaesthetics Oxymetazoline Pancreas – stimulate glucagon release Platelets – aggregation Axon terminals – reuptake NE Adipose – inhibits lipolysis Renal – inhibits reninĬlonidine systemic, inhibition of sympathetic tone and reduced BP Gi protein = decreased cAMP and PKA activity, K+ efflux Phentolamine (a1= a2) reversible blockade, t ½ 45 minsĬardiac stimulation due to a2 antagonism-> enhanced NE release-> severe tachycardia, arrythmias, MI Tamsulosin high affinity for a1A and D = contracts vascular smooth muscle in prostrate Lowers BP and increases HR due to baroreflex activation Phaeochromocytoma txĪE: orthostatic hypotension, nasal stuffiness, inhibition of ejaculation Phenoxybenzamine (a1>a2) Irreversible blockade = long duration >1 day Prazosin, doxazosin (a1 >a2) lower BPHTN, BPH tx Tyramine (similar to NE) intensified in patients on MAO-I = avoid high tyramine containing foods Atomoxetine (Reduced reuptake of NE) Phenmetrazine Methylphenidate (ADHD tx) Modafinil (narcolepsy tx) increases synaptic concentration of NE/ DA/ 5HT3/ glutamate Midodrine treatment of orthostatic hypotension Decreases HR due to vagal reflex Norepinephrine (a1=a2, b1>b2) Phenylephrine (a1>a2 >b) not inactivated by COMT longer duration of action than catecholamines Mydriatic, decongestant, raise BP. Vascular smooth muscle (arterial and venous vasoconstriction) Reduce blood flow to kidneys, GIT Prostate, bladder base and urethral sphincter – contraction, continence Dilator pupillae – mydriasis and outflow aqueous humour Gonads – male prostate contraction/ ejaculation and female uterine contractions Skin – piloerection Heart – increased contractility Gq protein coupled = increased IP3/DAG Stimulated by DA at high doses.
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