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Stack #358040

The extent of desensitization of receptors is dependent on __________________ the intrinsic activity of the agonist (i.e. partial agonists cause much less receptor desensitization.
G-alpha-s receptor subunit activates _____________ adenyl cyclase; leading to increased cyclic AMP levels.
Increased cyclic AMP levels and increased calcium do what to the heart? Stimulates it; causes increased HR and contractility.
What type of levels of cAMP lead to contraction of smooth muscle? Decreased levels of cAMP.
G-alpha-q receptor subtype activates __________ causing increased levels of _______ to be made Phospholipase-C-beta enzymes; Ca++
Increased PLC levels and Ca levels do what to smooth muscle? And which subunit is this mediated by? Causes contraction. G-alpha-q.
G-alpha-i inhibits what? And which receptor subtype's action is this opposing? Adenyl cyclase; Subtype G-alpha-s.
Inhibiting adenyl cyclase action leads to decreased __________ levels? And which muscle does this cause contraction in? cAMP levels; smooth muscle.
G-beta-gamma subtype activates _____ channels through release from G__/__ K+, i/o .
Activation of K+ channels causes ___________ and stops what from being released? Hyperpolarization; neurotransmitter.
Along with activating K+ channels, what does G-beta-gamma activate? GPCR kinases (i.e. beta-adrenergic receptor kinase, Beta-ARK).
What does phosphorylating GPCR's do? Causes receptors to be de-sensitized
Which G protein goes with alpha-1 receptors? Gq
Which G protein goes with alpha-2 receptors? Gi
Which G protein goes with B receptors? Gs
Which effector enzyme goes with alpha-1 receptor and G protein Gq? +phospholipase C
Alpha-2 receptor has which G protein? And which effector enzyme? G protein Gi; and -adenyl cyclase.
Beta-receptor has which G protein? And which effector enzyme? G protein s; Effector enzyme +adenyl cyclase.
Beta receptors and Gs subunit has what effects when they are stimulated? 1. Activates adenyl cyclase which leads to increased cAMP levels; this leads to increased Ca+ in the heart (and increased contractility)
Which two receptors affect adenyl cyclase levels (either increasing or decreasing)? Receptor alpha-2 and the beta receptors
Which receptor does not affect adenyl cyclase levels but affects Ca and PLC enzymes? Alpha-1 receptor.
What are indirect agonists? Drugs that cause an unregulated release of a transmitter (an endogenous transmitter)
What are the two ways that indirect agonists work? 1. By competing with NE for reuptake into the nerve terminal and uptake into vesicles. 2. Also, displace NE from the vesicles and nerve terminal, causing a build up in the nerve synapse.
How do mixed-function agonists work? They work directly as agonists on receptors; as well as by both indirect effects (displacing and releasing NE).
What are tocolytic agents? And what class are they from? Drugs used to inhibit uterine contractions in premature labor; Beta-agonist.
G protein 'Gq' is used with which receptor? Receptor alpha-1.
G protein 'Gi' is used with which receptor? Receptor alpha-2.
G protein 'Gs' is used with which receptors? The Beta receptors.
Alpha-1 (G-alpha-q) affect which tissues and organs? Major blood vessels (excepting skeletal and hepatic), eye, GI sphincters, Bladder sphincters, and liver.
What effect does alpha-1 (G-alpha-q) have on the eye? Causes mydriasis (pupil dilation), by contracting the radial muscles.
Alpha-1 (G-alpha-q) subtype affects GI sphincters how?
Created by: 81277