Imagine the following hypothesis: Long-term, heavy coffee consumption (let's say coffee made from the Robusta beans grown in sub-Saharan Africa, so very high in caffeine) makes the person susceptible to cardiac arrest due to myocardial hypoxia. Describe a possible mechanism explaining this. Note: cardiac arrest is mentioned for dramatic effect. It has nothing to do with your answer. (6 pts)
The relaxation of the cardiac vascular smooth muscle cells occurs when the adenosine binds to the A2a receptor on the muscle wall which results into generation of the c-AMP and thus activates the protein kinases for hyperpolarisation and thus relaxation of the muscle .
The caffeine acts as a adenosine antagonist and causes competitive binding to the G-coupled receptor A2a causes decreases in cardiac vasodilation and stress and as a result it causes the insufficient blood flow to the cardiac muscle thus myocardial hypoxia. The prolonged myocardial hypoxia may cause cardiac arrhythmias and cardiac arrest.
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