Lecture 10 (EXAM 2) Flashcards
(27 cards)
What are the cholinergic and adrenergic receptors?
Cholinergic: Parasympathetic -> Muscarinic, nicotinic, ganglionic
Adrenergic: Sympathetic -> alpha 1,2 / ß1,ß2, ß3
Why are nicotinic receptors, not the best drug targets?
Because there are widespread (ganglia, medulla, skeletal muscles, brain) and may cause multiple adverse effects
What are the sympathetic and parasympathetic effects on the eye (pupils)?
Sympathetic: contraction of the radial muscle
-> Pupils DILATED (bigger)
Parasympathetic: contraction of the Sphincter muscle
-> Pupils constricted (smaller)
Meaning of Mydriasis and Miosis
Mydriasis: Pupils dilated (bigger) - SYMPATHETIC
Miosis: Pupils constricted (smaller) - PARASYMPATHETIC
What are first and second messenger in signaling system?
-f.e. an agonist binding to the receptor would be the first messenger
-the G-protein associated with the receptor is the second messenger -> GDP cleaves off and GTP binds to the G-protein causing further downstream effects
What are the two metabolites that activate the signaling in the Phospholipase C pathway?
-DAG activating the protein kinase C (PKC)
-IP3 stimulating Ca release -> activating a protein kinase
How does the Acetylcholine pathway start?
-Cholin (with diet, f.e. bread) uptake by CHT (transporter)
-combined with Acetate to form Acetylcholine (with ChAT enzyme)
-ACh gets transported into vesicles
How is ACh released from the pre-synaptic nerve terminal?
Action potential comes down, and causes depolarization -> the voltage-dependent Ca-channel opens and Ca2+ activates vAMP
-vAMPs will cause the vesicle to fuse with the membrane -> which causes ACh release into the synaptic cleft
What is the role of Vesamicol?
It inhibits ACh uptake into the vesicles in the presynaptic neuron
What is the effect of the Botulinum toxin?
It inhibits vAMPS and prevents ACh release
How is the ACh activity stopped?
-Acetylcholine is broken down into Choline and Acetate by the Acetylcholineesterase
What are the effects of Parasympathomimetics?
-Things that act like ACh -> cholinergics
What are the muscarinic effects of the heart?
- bradycardia (slow rate, negative chronotropy)
- decreased conduction (negative dromotropy)
- decrease contraction force (negative inotropy)
-some muscarinic effect of vasodilation
What are the Parasympathomimetic effects in the GI?
increased tone and motility of the wall muscles and relaxation of sphincters
What are the Parasympathomimetic effects on the bladder?
the body (detrusor mm) contracts while sphincters relax
Parasympathomimetic effects on the lungs
bronchoconstriction and increase secretion
Parasympathomimetic effects on the eye
contraction of the ciliary mm (lens) and circular mm of the iris
Parasympathomimetic effects on the exocrine glands
promotes secretion
What is a Sludge response?
Response to an increased muscarinic stimulation
f.e. eating the wrong mushroom
How are Cholinergic stimulants different from Acetylcholine?
-They have similar structures and are considered choline esters
-they have less vulnerable to Cholinesterase, different strengths of Muscarinic and nicotinic action
-Synonyms:
Parasympathomimetics
Cholinergic agonists
Muscarinic agonists
Cholinoceptor stimulants
Examples of choline esters
-Methacholine (Acetylcholine with a methyl group)
-Carbachol (Amid group instead of an acetyl group)
-Bethanechol (Amid group and a methyl group)
What is the indication of Bethanechol?
Cholinergic agonist
Brand name: Duvoid
postpartum and postoperative nonobstructive urinary retention and it also can counteract bladder dysfunction
-> relieve difficulties in urinating
What is the indication of Carbachol?
Cholinergic agonist
Miotic agent (small pupils) -> Pupils contract
-treatment of glaucoma
What are muscarinic agonists
-Natural alkaloids (not choline esters)
-Muscarine - considered a toxin -> from mushrooms, several types
no clinical use
-Pilocarpine – prototype (class representative)
