PHA 3112 Lecture Notes - Lecture 2: Benign Prostatic Hyperplasia, Adrenergic Receptor, Orthostatic Hypotension

• School: University of Ottawa
• Department: Pharmacology
• Course: PHA 3112
• Professor: Pierre Fortier

Document Summary

Adrenergic agonists are also referred to as sympathomimetic. Adrenergic receptors activated by 4 basic mechanisms: 1] direct receptor binding, mimicking actions of natural transmitters (norepinephrine (ne), epinephrine, dopamine). [2] acting on terminals of sympathetic nerves to cause ne release. [3] blockade of ne reuptake: ne reuptake into terminals of sympathetic nerves is major mechanism for terminating adrenergic transmission, blocking ne reuptake causes ne to accumulate within synaptic gap. [4] inhibition of ne inactivation: some ne in terminals of adrenergic neurons are inactivated by monoamine oxidase (mao), drugs that inhibit mao increase ne available for release & enhance receptor activation. All drugs act by direct receptor activation except for ephedrine (combo of direct receptor activation & ne release) Indirect-acting adrenergic agonists are used to activate adrenergic receptors in cns. Indirect-acting sympathomimetics (amphetamine, coke) causes activation of adrenergic receptors in periphery. Table 17 1 mechanisms of adrenergic receptor. 2 major chemical classes of adrenergic agaonists: catecholamines & 2) noncatecholamines.