The effect of Ca2+, Cd2+ and Ni2+ on detergent-permeabilized vascular smooth muscle from the shark, Squalus acanthias
Version 2 2024-06-03, 11:32Version 2 2024-06-03, 11:32
Version 1 2017-04-28, 14:41Version 1 2017-04-28, 14:41
journal contribution
posted on 2024-06-03, 11:32authored byDH Evans, E Chipouras, T Toop, John DonaldJohn Donald
We examined the effect of Ca2+, Cd2+, or Ni2+ on vascular smooth muscle intracellular proteins involved in contraction, using rings of detergent-permeabilized aortae from the spiny dogfish, Squalus acanthias. Addition of Ca2+ stimulated contraction of the vascular smooth muscle, and permeabilization by treatment with Triton X-100 increased the sensitivity to Ca2+ nearly 5 log units, demonstrating that this protocol left contractile and regulatory proteins intact. Addition of 1 microM calmodulin did not increase the sensitivity of the rings to Ca2+, suggesting that this preparation is not leaky to this regulatory protein. Neither Cd2+ nor Ni2+ stimulated contraction of permeabilized rings demonstrating that the previously-described contractile action of these heavy metals is not mediated by direct stimulation of intracellular proteins, rather by interaction with sarcolemmal proteins.