Extensive skinning of cell membrane diminishes the force-inhibiting effect of okadaic acid on smooth muscles of Guinea pig hepatic portal vein.
The influences of cell membrane permeabilization (skinning) on the okadaic acid-induced inhibition of vascular smooth muscle contraction were studied in guinea pig hepatic portal vein. Pretreatment by 1 microM okadaic acid in the absence of Ca(2+) suppressed subsequent submaximal Ca(2+)-induced contraction in preparations permeabilized with Staphylococcus aureus alpha-toxin or beta-escin, but not in those treated with saponin or Triton X-100. The SDS-PAGE of elutants from the preparation suggests that the loss of the inhibitory effect of okadaic acid in preparations skinned with saponin or Triton X-100 results from the leakage of some cellular components with a molecular mass of 67 to 200 kDa.
Department of Physiology, Tokyo Medical University, Shinjuku-ku, Japan. masaru@tokyo-med.ac.jp
Masaru
M
Watanabe
Hiromi
H
Takano-Ohmuro
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D004928:Escin / Q000494:pharmacology; D006168:Guinea Pigs; D007476:Ionophores / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D019319:Okadaic Acid / Q000494:pharmacology*; D011169:Portal Vein / Q000187:drug effects / Q000378:metabolism*; D010738:Type C Phospholipases / Q000494:pharmacology
D007476:Ionophores; D019319:Okadaic Acid; D004928:Escin; D010738:Type C Phospholipases; D002118:Calcium