new_n_lost
Politically InCorrect
Topics: 653
Posts: 6,086
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The normal answer to the question is usually NE because it causes Reflex Bradycardia but since the nerves in a recent transplant patient are reattaching themselves then only Dobutamine will not cause any tachcardia as its only increasing the force in contraction and nothing else,
All the other drugs will eventually increase the HR even Amphetamines cos they do induce a dopamine release everywhere.
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| macintosh
Forum Elite
Topics: 38
Posts: 178
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First off I think it is a difficult question, and my honest answer to it is the one I am most familiar with, that is I do not know. But for the sake of practice, this is how I shall reason the answer.
All the drugs given in the answer choices have effect on the heart rate. This is because all of the choices are beta 1 adrenergeic agonist. As the heart is transplanted, reflex is not present.
Dobutamine should have less effect on increasing heart rate than the other choices. This is because dobutamine is primarily used in the clinical setting as an inotropic agent so as to increses the force of contraction. I think it has less chronotropic effect as it does not stimulate the dopamine receptors like all the remining choices do.
So my answer is Dobutamine.
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| maoudoody
Forum Elite
Topics: 23
Posts: 435
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the right answer is amphetamine
cause it is an indirect sympathomimitic
it is one of the releasers of NE from nerves together with tyramine and ephedrine
this patient is a recepient for heart i.e the new heart is denervated
so only amphetamine is the least likely to cause tachyardia " no nerves to act upon and release NE"
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| maoudoody
Forum Elite
Topics: 23
Posts: 435
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all other drugs will act on b1 receptors
b1 receptors r present in san , avn, ventricular , atrial tissue, pirkunje, his bundle
so stimulation of b1 receptors in san will increase the heart rate
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| icarus
Forum Senior
Topics: 27
Posts: 149
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Please tell me that these questions are for your own pleasure ... if the real exam is at this lecvel ... everything is gone ...
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