45Ca2+movements induced by Ca2+chloride in isolated rat aorta under K+-free conditions

Wermelskirchen, D., Nebel, U., Wirth, A. & Wilffert, B., 22-Oct-1991, In : European Journal of Pharmacology. 192, 3, p. 403-408 6 p.

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Increasing the extracellular Ca2+concentration induced a dihydropyridine-insensitive contraction in the isolated rat aorta bathed in K+-free solution. To obtained further insight into the mechanisms of this contraction45Ca2+uptake measurements were carried out with isolated rat aorta. Increasing the extracellular Ca2+concentration from 0.63 to 5.0 mM enhanced the45Ca2+uptake from 186 ± 3 to 359 ± 12 dpm/mg ww (n = 8). Under K+-free conditions increasing the extracellular Ca2+concentration from 0.63 to 5.0 mM enhanced the45Ca2+uptake from 184 ± 4 to 541 ± 6 dpm/mg ww (n = 12) and elicited an increase in tension of 10.0 ± 0.4 mN (n = 9). The Ca2+-induced45Ca2+uptake was not affected by the Ca2+channel antagonists, nifedipine (L-type), flunarizine (L- and T-type) and ω-conotoxin (N-type). Amiloride, a blocker of the Na+/Ca2+exchange, indomethacin, a blocker of prostaglandin synthesis, the local anaesthetic, lidocaine, and the Ca2+overload blocker, R 56865, had no effect on Ca2+-induced45Ca2+uptake. Additionally, R 56865 did not affect the Ca2+-induced contractile response. The inorganic Ca2+entry blocker, lanthanum, reduced both the non-stimulated and stimulated45Ca2+uptake and inhibited the Ca2+-induced contractile response. We would like to suggest that the45Ca2+uptake induced by Ca2+under K+-free conditions enters the cell via the leakage Ca2+channel, because lanthanum was an effective antagonist and a significant contribution of any other Ca2+pathway could not be demonstrated.
Original languageEnglish
Pages (from-to)403-408
Number of pages6
JournalEuropean Journal of Pharmacology
Issue number3
Publication statusPublished - 22-Oct-1991


  • 45Ca2+uptake, Aorta (rat), Ca2+channels (leakage), Ca2+entry blockers, amiloride, calcium antagonist, calcium channel, calcium chloride, flunarizine, indometacin, lanthanum, lidocaine, n [1 [4 (4 fluorophenoxy)butyl] 4 piperidinyl] n methyl 2 benzothiazolamine, nifedipine, omega conotoxin, radioisotope, animal tissue, aorta, article, calcium transport, concentration response, controlled study, nonhuman, priority journal, rat, smooth muscle contractility

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