our findings suggest ( a ) that the nondonnan distribution of cl in smooth muscle is not caused by sequestration in organelles , and that considerations of osmotic equilibrium and electroneutrality suggest the existence of unidentified nondiffusible anions in smooth muscle , ( b ) that nuclei do not contain concentrations of na or ca in excess of cytoplasmic levels , ( c ) that mitochondria in pamv smooth muscle do not play a major role in regulating cytoplasmic ca during physiological levels of contraction but can be massively ca loaded in damaged cells , and ( d ) that the in situ transmitochondrial gradients of k , na , and cl do not show these ions to be distributed according to a large electromotive donnan force .
C0026237
mitochondria
C0010834
cytoplasmic