Calcium current activated by muscarinic receptors and thapsigargin in neuronal cells.

• DOI: 10.1085/jgp.104.1.107
• Publication Date: 2004-05-13T23:51:34Z
• Authors: C Mathes; S H Thompson
• Keywords: Thapsigargin; BAPTA; Calcium in biology; Muscarinic agonist

The activation of muscarinic receptors in N1E-115 neuroblastoma cells elicits a voltage-independent calcium current. current turns on slowly, reaches its maximum value approximately 45 s after applying the agonist, is sustained as long agonist present, and recovers by one half 10 washing away. density 0.11 +/- 0.08 pA/pF (mean SD; n = 12). It absent zero-Ca++ saline reduced Mn++ Ba++. I(V) curve characterizing has an extrapolated reversal potential > +40 mV. observed heavily loaded with BAPTA indicating that entry pathway not directly gated calcium. In fura-2 experiments, we find causes elevation intracellular Ca++ due to both release influx. component signal requires external same time course receptor operated Calcium influx measured this way elevates (Ca++)i 89 41 nM (n 7). Thapsigargin, inhibitor Ca++/ATPase associated endoplasmic reticulum (ER), activates similar properties. 0.22 0.20 6). Thapsigargin activated Ba++ increased elevated Ca++. thapsigargin 82 35 nM. currents do sum, these procedures activate process. Carbachol cause from internal stores bears strong similarity calcium-release-activated nonexcitable (Hoth, M., R. Penner. 1993. Journal Physiology. 465:359-386; Zweifach, A., S. Lewis, Proceedings National Academy Sciences, USA. 90:6295-6299).