inthemist
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Why 'flushing' is included in sign of atropinization?
I think it should show sign of increasing sympathetic activity which is vasoconstriction of bl.vessels of skin--->leads to pale skin
please help , thanks 
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| inthemist
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I really want to know....
Is it anything with the receptor?
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| DrVirgo
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Good question. I guess you are wondering if cholinergic muscarinic drugs cause vasodilation, why does atropine which is an antimuscarinic also cause vasodilation instead of vasoconstriction, right?
Well, lets see if I can explain it...
Atropine blocks thermoregulatory sweat glands which are unique because they are under SYMPATHETIC CHOLINERGIC control (part of the sympathetic nervous system, but use Ach as a neurotransmitter). If these sweat glands are blocked, there is no way to dissipate heat, so as a REFLEX, the blood vessels DILATE, and there is vasodilation to exchange heat. This causes hyperthermia... Its all part of that mnemonic: dry as a bone, hot as a hare, red as a beat... etc...
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| asherif
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A very good explanation DrVirgo.
let me summarize it:
Atropin block thermoregulatory sweat glands(cholinergic) ===> no sweating ===> hyperthermia ===> Vasodilatation (to lose heat) ===> flushing (red skin due to vasodilatation)
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| drpkaur
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very good explanation Drvirgo and asherif...keep it up...
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| DrVirgo
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You got it asherif! Remember that the vasodilation is a reflex due to atropine and not a direct effect!
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