A lot of times drugs are developed for one purpose but, due to their mechanisms

Question

A lot of times drugs are developed for one purpose but, due to their mechanisms of action, end up having other effects as well. Through your rigorous testing of MuchoMacho, your novel drug that enhances skeletal muscle contraction, you've found that it also ha:s unintended effects on heart rate. The data from your most recent experiment is to the right. 160 140 120 to 100 You recorded the baseline heart rate in your subject and then administered one dose of MuchoMacho at 30 minutes, which produced a near instantaneous effect on heart rate. Based on all of this information, what is the MOST LIKELY mechanism of action for Much°Macho? (½ point) a) keeps L-type calcium channels open longer b) allows T-type calcium channels to open faster c) increases acetylcholine release onto the SA node d) increases crossbridge cycling 80 60 0 15 30 45 60 75 90 time (minutes)

Explanation / Answer

Answer is b) allows T-type calcium channels to open faster.

Explanation:The calcium current due to opening of T-type calcium channels completes the prepotential.

So, any drug that opens the T-type calcium channel faster, increases the slope of prepotential/pacemaker potential, thus making the pacemaker tissue to fire more frequently, and increases the heart rate.

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