Large-conductance calcium-sensitive BK channels are one of the potassium channels that hyperpolarize
the neurons and are encoded by KCNMA1 (6,7).
Oxt is thought to hyperpolarize
the pain signalcarrying nerves.
Since adenosine can vasodilate and hyperpolarize
the vascular smooth muscle cells (VSMC), it is considered an EDHF .
This influx of calcium appears necessary to stimulate the development of the mature form of the chloride ion transporter KCC2 (neuronal potassium-chloride symporter) that allows the neurons to hyperpolarize
to their adult resting potential.
Most agents that activate release of NO from the endothelium also hyperpolarize
both endothelial and smooth muscle cells (35).
Physiologically, activation of [BK.sub.Ca] channels would hyperpolarize
MASMCs, thereby closing VDCCs, reducing intracellular [Ca.sup.2+] and relaxing SMCs (Nelson and Quayle 1995).
When activated, these receptors hyperpolarize
the membrane potential and/or fix the membrane potential at voltages below the action potential threshold.
The PIA sends projections to NGC (74), NMC (71,75) and NPM (76) of the medullary region, which in turn project to the spinal cord (72,75,77) to hyperpolarize
motoneurons to control the spinal circuits for inducing atonia during REM sleep (78,79).
Another vasodilator action of the endothelium is mediated by the release of substances-including nitric oxide, prostacyclin, and eicosatrienoic acid-that hyperpolarize
smooth muscle by activating calcium-dependent potassium channels and are collectively referred to as endothelium-derived hyperpolarizing factors (22).
The membrane will become depolarized next to the initial site of depolarization, and the potential will increase (i.e., hyperpolarize
) with distance away from the initial site of depolarization until the membrane potential is equal to the resting potential.
First of all, although it produces a proper AP at all the tested [[[K.sup.+]].sub.o], it behaves nonphysiologically when [[[K.sup.+]].sub.o] is lower than 4 mM: the RMP depolarizes instead of hyperpolarize
and, as a consequence, the [APD.sub.90] also goes in the opposite way (shortening) and dV/[dt.sub.MAX] dramatically decreases.
The two retinas differ morphologically and physiologically: the ciliary photoreceptors of the distal retina hyperpolarize
in response to light, whereas the rhabdomeric photoreceptors of the proximal retina depolarize in response to light (Hartline, 1938; Wald and Seldin, 1968; McReynolds and Gorman, 1970; Gomez and Nasi, 1994).