The effects of verapamil, nifedipine and diltiazem were studied during anoxia in freshly isolated rat hepatocytes cast in agarose gel threads and perfused with Krebs-Henseleit bicarbonate buffer (KHB). Cytosolic free calcium (Ca(i) 2+) was measured with aequorin. Anoxia was induced for 2 hr by saturating the perfusate with 95% N 2-5% CO 2. In the control group, anoxia increased Ca(i) 2+ in two distinct phases:the first rise reached a mean value of 389±35 nM (p <0.001). The second major peak reached a maximum value of 1.45 ± 0.42 μM after 1 hr (p <0.001). LDH release increased 2.5- fold during the first hr of anoxia and 6-fold during the second hr (p <0.001). During reoxygenation, Ca(i) 2+ and LDH returned to control levels within 45 min. When Ca 2+ was removed from the perfusate during the anoxic period, the second major surge in Ca(i) 2+ was totally abolished and the rise in LDH release was significantly reduced Ca 2+ channel blockers did not prevent the increase in Ca(i) 2+ and the rise in LDH release. On the contrary, high concentrations of nifedipine and diltiazem significantly increased anoxic cell injury as measured by LDH and trypan blue uptake. Since the rise in Ca(i) 2+ was not suppressed by the 3 Ca 2+ antagonists used in these studies, Ca 2+ channels of the L-type are probably not involved in the massive increase in Ca(i) 2+ evoked by anoxia. These studies also suggest that the cell injury and LDH release induced by anoxia may be related to the increase in Ca(i) 2+.
|Number of pages||5|
|Journal||Transplantationsmedizin: Organ der Deutschen Transplantationsgesellschaft|
|Publication status||Published - 1994|
ASJC Scopus subject areas
- Immunology and Allergy