Effects of calcium channel blockade in canine saphenous veins after storage at -190 degrees C.

1. Canine saphenous veins were investigated in vitro either within 24 h after removal or after storage at -190 degrees C for 4-5 weeks of foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. Contractions and 45Ca2+ uptake in response to both depolarization and guanfacine were studied in the absence and presence of the calcium channel antagonists diltiazem, verapamil, nifedipine and the two stereoisomers of a 1,4-dihydropyridine derivative, namely the (+)-(S) enantiomer and the (-)-(R) enantiomer of 202-791 (isopropyl 4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-2,6-dimethyl-5-nitro-3- pyridinecarboxylate). 3. Comparison of the data obtained on unfrozen and frozen/thawed veins revealed a good preservation of both contractile responsiveness and 45Ca2+ uptake mechanisms after storage at -190 degrees C. 4. It is suggested that cryopreservation is a useful technique for storing venous smooth muscle for pharmacological studies.