Intracellular Calcium Ions Modulate Permeability of the Peritoneal MesotheliumIn Vitro

Abstract

The authors studied the in vitro effect of a calcium-channel-blocker -verapamil, local anesthetic -bupivacaine and a calcium ionophore -A23187 on the permeability of the monolayer mesothelium from the rabbit's mesentery. Verapamil and bupivacaine increased transmesothelial flux of calcium while A23187 increased calcium transport only transiently. Verapamil augmented the permeability of the mesothelium to inulin and urea. However A23187 decreased the transmesothelial flux of inulin only whereas it increased the transport of urea. From this study we have concluded, that intracellular calcium may determine the permeability of the peritoneal mesothelium.Various important biological processes like muscle contraction, secretion of transmitters and hormones, and control of epithelial permability seem to be dependent on intracellular calcium-ion activity (1–4). Our previous paper suggested that a local anesthetic, bupivacaine, produces its effect on the peritoneal mesothelium through interaction with the cytoskeleton of the epithelial cells, and with the mem brane's calcium transport (5). In addition Palant et al found that the permeability of another leaky epithelium, that from the Necturus gallbladder, depends on the extracellular calcium concentrations and may be altered by drugs, which interfere with the entrance of these ions into the epithelial cells (6). Therefore, we decided to study the role that calcium ions may play in the transport of solutes across the peritoneal mesothelium in vitro.