If channels are permeable to ____ and ____. How does the presence of these channels lead to spontaneous depolarization? Which part of the conduction system has the highest amount?
- If channels are permeable to ____ and ____. How does the presence of these channels lead to spontaneous depolarization? Which part of the conduction system has the highest amount?
Funny channels or Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels in the heart are stimulated by levels of intracellular cyclic adenosine monophosphate (cAMP) by a process modulating the autonomic nervous system's control of heart rate and also by hyperpolarization of voltage. When the membrane potential is quite negative (about -60 mV) at the end of the repolarization point, ion channels open up that conduct gradual inward (depolarizing) current, which is known as funny currents (If).
In particular, it can be shown that blocks in funny channels by "pure heart rate-reducing" agents such as ivabradine (at selective doses) promote a slowdown by lowering the rate of diastolic depolarization, with little change in the duration of the action potential.
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