Adrenergic Drugs Flashcards
what is the major mechanism for termination of action of adrenergics?
reuptake
what are the ways that drugs affect adrenergic transmission?
norepinephrine synthesis
vesicle uptake of neurotransmitter
release of neurotransmitter
receptor interactions
reuptake
metabolism
what are the adrenergic receptors?
alpha receptors: alpha1 and alpha2
beta receptors: beta1, beta2, and beta3
dopamine receptors: D1-D5
what is the response to receptor activation of alpha1 receptors?
contraction (arteries, veins, uterus)
what is the response to receptor activation of alpha2 receptors?
inhibit norepinephrine release at presynaptic nerve endings
decrease sympathetic tone at postsynaptic in CNS
what is the response to receptor activation of beta1 receptors?
increased heart rate and force of contraction
what is the response to receptor activation of beta2 receptors?
dilation of arterioles
relaxation of bronchial and uterine smooth muscle
what is the response to receptor activation of beta3 receptors?
increased lipolysis in lipocytes
what is the response to receptor activation of D1 receptors?
dilation of arterioles of kidney and mesentery
what is essential in activation of alpha1 receptors?
calcium
what happens intracellularly after an alpha2 receptor is activated?
decrease in cAMP
what happens intracellularly after a beta receptor is activated?
increase in cAMP
how can beta2 receptors and alpha1 receptors lead to opposite actions through a similar route?
MLC is phosphorylated in alpha1, leading to smooth muscle contraction
MLC is not phosphorylated in beta2, leading to smooth muscle relaxation
what is the mechanism of action for alpha1 receptors?
increase calcium
what is the mechanism of action for alpha2 receptors?
decrease cAMP
open potassium channels
close calcium channels
what is the mechanism of action for beta1, beta2, and beta3 receptors?
increase cAMP
increased cAMP increases calcium in heart