hyperpolarization

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hyperpolarization

 [hi″per-po″ler-ĭz-a´shun]
any increase in the amount of electrical charge separated by the cell membrane and hence in the strength of the membrane potential. In cardiology this is the process by which an electrical fiber, at the end of phase 3 repolarization, becomes more negative than usual.

hy·per·po·lar·i·za·tion

(hī'pĕr-pō'lăr-i-zā'shŭn),
An increase in polarization of membranes of nerves or muscle cells; the reverse change from that associated with excitatory action.

hy·per·po·lar·i·za·tion

(hī'pĕr-pō'lăr-ī-zā'shŭn)
An increase in polarization of membranes of nerves or muscle cells, which makes the cell less sensitive to any stimulus; the reverse change from that associated with excitatory action.

hyperpolarization

A change in the value of the resting membrane potential towards a more negative value. The inside of the cell becomes more negative than the outside. Hyperpolarization is inhibitory because the membrane potential moves away from the neuron's threshold at which an action potential could occur. Example: the retinal photoreceptor potentials when stimulated by light. See depolarization; receptor potential; resting membrane potential; synapse.

hy·per·po·lar·i·za·tion

(hī'pĕr-pō'lăr-ī-zā'shŭn)
Increased polarization of membranes of nerves or muscle cells.
References in periodicals archive ?
[alpha]-2 agonists act by altering transmembrane potential and ion conductance, thus cause hyperpolarisation of nerves in the brainstem (Locus coeruleus).
Proper function of outer hair cells is intrinsically tied to their motile nature and ability to change length upon membrane hyperpolarisation and depolarisation (8).
The activation of [Na.sup.+]-[K.sup.+] ATPase leads to a shift of potassium ions intracellularly, resulting in hypokalaemia and hyperpolarisation of muscle cell membranes [1].
Moderate mitochondrial [Ca.sup.2+] increase may disinhibit the respiratory chain leading to [DELTA][[PSI].sub.m] hyperpolarisation [21] which in turn is accompanied by increasing superoxide anion formation [22].
Excitatory signals will cause a change in the resting potential toward the positive (depolarisation), while inhibitory signals will cause the membrane potential to become more negative and more difficult to excite (hyperpolarisation).
In the last few years, several approaches involving 'hyperpolarisation' of nuclear spins have emerged that are poised to revolutionise NMR spectroscopy.
The analgesic action of intrathecal [alpha]2 adrenoreceptors agonist is by depressing the release of C-fiber transmitters which explain the prolongation of the sensory block and by hyperpolarisation of postsynaptic dorsal horn neurons which explain the prolongation of the motor block.
Presynaptic stimulation of [[alpha].sub.2] receptors inhibits neurotransmitter release and postsynaptic stimulation prevents neuronal transmission through hyperpolarisation [10].
1993) thus leading to exit of [K.sup.+] following its chemical gradient, cell membrane hyperpolarisation, [Cl.sup.-] exit and thus cellular loss of KCl with osmotically obliged water (Lang et al.
Tumescence relies on NO action on the efflux of calcium (C[a.sup.2+]) and hyperpolarisation of the smooth-muscle cell potassium ([K.sup.+]) to cause relaxation of the arteries with a decrease in venous drainage.
It is tempting to speculate that such a [Gd.sup.3+]-insensitive subset is formed by [K.sup.+] channels [32], which may confer hyperpolarisation of the plasma membrane and thereby promote [Ca.sup.2+] influx into endothelial cells 43].