What two types of receptors do NA act on?
Alpha and Beta. Generally alpha excitation, Beta relaxation of effector cells.
List in order of sensitivity the types of chemicals which react with alpha adrenoreceptors.
List in order of sensitivity the types of chemicals which react with beta adrenoreceptors.
Effects of Alpha 1 adrenoreceptor stimulation.
Vasoconstricion, GI smooth muscle relaxation, Salivary secretion (going to eat) and hepatic glycgenolysis (give energy to eat). NASAL AND OCULAR DECONGESTANTS.
Effects of Alpha 2 adrenoreceptor stimulaiton.
Vasoconstriciton (post junctional), Inihibition of transmitter release (pre junctional), inibition of insulin release. Platelet aggregation.
Effects of Beta 1 adrenoreceptor stimulation.
Increased cardiac rate and force.
Effects of Beta 2 adrenoreceptor stimulation.
Vasodilation in muscle, Brochodilation, Relaxation of visceral smooth muscle, Hepatic glycogenolysis.
Effects of Beta 3 adrenoreceptor stimulation.
Tyrosine to DOPA, then Dopamine, Noradrenaline and finally Adrenaline.
What drug would you give to increase levels of dopamine in the brain?
How does Levodopa increase levels of Dopamine?
Levodopa increase levels of DOPA which is converted by DOPA carboxylase into Dopamine.
What enzymes are involved in the conversion of Tyrosine to adrenaline.
Hydroxylase, Decarboxylase, Beta Hydroxylase, Phenylethanoloamine N-methyltransferase.
What should you give along with Levodopa?
A peripheral DOPA decarboxylase inhibitor. This should be given to prevent dopamine production in the peripheral nervous system and prevent hyperdopaminergia.
Hyperdopaminergia is associated with what?
Blocks vesicle transport of Noradrenaline.
Drugs which affect NA storage.
Reserpina, MAO inhibitors.
Drugs blocking the release of NA.
Guanethidine, Bretylium, go through uptake 1 and abolish response to nerve stimulation.
Drugs which cause NA release even without nerve stimulation.
Tyramine, Amphetamines and Ephedrine. Enter via uptake 1, displace NA from vesicles. Cause effects similar to NA in the sympathetic nervous system.
Drugs that increase or decrease release of NA?
Stuff that affect alpha 2 receptors.
Types of MAO inhibitors.
Moclobemide - depression, Pargyline, Selegeline - parkinson's disease.
Tyramine cheese reaction.
When food containing tyramine is consumed and the patient is taking a MAO inhibitor, there is the chance that the patient may suffer a hypertensive crisis.
Problem with MAOI.
When ingested orally they affected the digestion of dietary amines.
Malignant hypertension - cause acute impairment of one or more organ systems. The blood pressure should be lowered slowly. SYSTOLIC > 180, DIASTOLIC > 120.
Use of pseudoephedrine?
Inhibitors of uptake 1.
Tricyclic antidepressants - cocaine, aphetamines and guanethidine.
Inhibitors of uptake 2.
Effects of uptake inhibitors.
Enhance transmission. Creates euphoria.
Catechol-O-methyl transferase. Degrades catecholamines; dopamine, noradrenaline, epinephrine.
Alpha 1 antagonist.
Zosin, Inhibit vasoconstriction, lower blood pressure. Relax smooth muscle in baldder.
Alpha 2 antagonist.
Clonidine, selective. Inhibit NA release, lowers blood pressure, anxiolytic. Used in galucoma to reduce intraocular pressure. Yohimbine - erectile dysfunction.
Non selective alpha antagonist.
Phentolamine, Blocks effects of excess NA. Side effects - tachycardia, nasal congestion (due to negative feedback).
Non selective B1 agonists.
Cavedilol (+A1 as well), Oxprenolol.
Selective B2 agonist.
Selective B2 antagonist.
Non selective B2 antagonist.
Effect of B2 antagonists.
Worsen asthma and decrease anxiety (skeletal muscle tremor).
Selective B3 agonist.
BRL 37344 .
Non selective B3 antagonist.
Non selective Beta agonist.