Mechanosensitive nonselective cation channels in the antiluminal membrane of cerebral capillaries (blood-brain barrier).
Single stretch-activated (SA) cation channels have been investigated in the antiluminal membrane of freshly isolated brain capillaries. SA-channels did not distinguish between K+ and Na+ ions and were also permeable to Ca2+ and Ba2+ ions. With monovalent cations in the patch pipette the single-channel conductance was 37 pS and with the divalent cations Ba2+ and Ca2+ slope conductance was 16 and 19 pS, respectively. The open probability of the SA-channel increased with increasing negative pressure as well as with depolarization. Cell swelling induced by hypotonic shock activated the SA-channels in cell-attached experiments. The contribution of SA-channels to the regulation of cerebrospinal fluid in brain edema is discussed.
Popp
R
R
Max-Planck-Institut für Biophysik, Frankfurt, FRG.
Hoyer
J
J
Gögelein
H
H
D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism; D002196:Capillaries / Q000502:physiology*; D002412:Cations / Q000378:metabolism; D002560:Cerebrovascular Circulation; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011188:Potassium / Q000097:blood / Q000378:metabolism; D013314:Stress, Mechanical; D013552:Swine
D002412:Cations; D007473:Ion Channels; D011188:Potassium