depolarizzati

Depolarizzati is the plural form of depolarizzato and refers to cells or tissues that have undergone depolarization, a change in the transmembrane potential in which the inside of the cell becomes less negative relative to the outside. This state contrasts with the polarized, or resting, membrane potential maintained by most cells.

In physiology, depolarization is a key step in excitability. It typically occurs when excitatory stimuli open voltage-gated ion channels, especially sodium (Na+) channels, allowing an inward Na+ current that reduces the membrane potential. If the depolarization reaches a threshold, an action potential is generated: a rapid upstroke due to further Na+ influx, followed by inactivation of Na+ channels and opening of potassium (K+) channels that restore the membrane potential during repolarization, often followed by a brief hyperpolarization.

Depolarization plays a central role in the function of neurons, skeletal muscle, and cardiac muscle. In neurons, it initiates electrical signaling and neurotransmitter release. In cardiac tissue, coordinated depolarization triggers contraction and drives the cardiac cycle; the sequence of atrial and ventricular depolarization is reflected in the electrocardiogram as the P wave and the QRS complex, respectively.

Detection and study of depolarization employ electrophysiological methods and body-surface or intracardiac electrodes. Abnormal patterns of depolarization can indicate pathology, such as ischemia, electrolyte disturbances, or conduction blocks, and may be modulated by drugs that affect ion channels. The term is used broadly to describe any state where the transmembrane potential becomes less negative, i.e., a depolarized state.