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.

Farlex Partner Medical Dictionary © Farlex 2012

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.

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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.

Medical Dictionary for the Dental Professions © Farlex 2012

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).

ROLE OF DEXMEDETOMIDINE AND CLONIDINE AS ADJUVANTS WITH ROPIVACAINE IN EPIDURAL ANAESTHESIA-A COMPARATIVE STUDY

Proper function of outer hair cells is intrinsically tied to their motile nature and ability to change length upon membrane hyperpolarisation and depolarisation (8).

A Novel Variant in SYNE4 Confirms its Causative Role in Sensorineural Hearing Loss

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].

Graves' Disease Presenting with Periodic Paralysis to the Emergency Department

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].

Targeting TRPM2 Channels Impairs Radiation-Induced Cell Cycle Arrest and Fosters Cell Death of T Cell Leukemia Cells in a Bcl-2-Dependent Manner

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).

Electricity in the brain

In the last few years, several approaches involving 'hyperpolarisation' of nuclear spins have emerged that are poised to revolutionise NMR spectroscopy.

Ames Laboratory Installs Instrument To Study Materials At Atomic Level

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.

A randomized controlled double-blinded prospective study of the efficacy of low dose of dexmedetomidine as an adjuvant to intrathecal bupivacaine in hysterectomies

Presynaptic stimulation of [[alpha].sub.2] receptors inhibits neurotransmitter release and postsynaptic stimulation prevents neuronal transmission through hyperpolarisation [10].

Comparison of postoperative analgesic effect of intrathecal clonidine and fentanyl added to bupivacaine in patients undergoing cesarean section: a prospective randomized double-blind study

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.

Stimulation of suicidal erythrocyte death by trans-cinnamaldehyde

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.

The physiology of erection and its relationship to the management of erectile dysfunction: the physiology of erection is central to the management of erectile dysfunction

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].

Enhanced [Ca.sup.2+] entry and tyrosine phosphorylation mediate nanostructure-induced endothelial proliferation