Question

How does high dose of muscarinic agonists cause hypertension since there is no parasympathetic nerve innervates vascular smooth muscle?

Answer 1

keep in mind that an muscarinic agonist may have nicotinic efect

Answer 2

really? I haven't known that.could you give me some concepts about the mechanism?? I am confused with this lesson T T

Answer 3

sure!! in a clinical situation, when we put atropine IV, at the beginning there will be a parasimpatic effect(muscarinic and nicotinic ) but some minutes later the simpatic system tries to compensate with an adrenergirc discharge which obviously raises the blood presure.

Answer 4

you mean it is the compensation mechanism of our bodies that causes hypertension?..so why it doesn't cause hypertension with low dose?

Answer 5

In low dose,it causes vasodilationd because of NO production and NE reduction
let me guess.in high dose,it arouses compensation with long duration far from drug action??

Answer 6

muscarinic drugs do not cause tachycardia; muscarinic agonist does not cause vasoconstrictor nor hypertension; muscarinic agonists are parasympath- omimetics, and will cause all of the peripheral effects coded by the mnemonic, DUMBBELSS except for excitation of skeletal muscle.
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