Action of cyclic AMP on intracellular calcium concentration and bursting activity

In order to clarify its role in the provocation of seizure activity, the effects of cyclic AMP were examined on the intracellular calcium concentration of pentylenetetrazol (PTZ)-sensitive neurons as well as of PTZ-non-sensitive neurons of the Japanese land snail, Euhadra peliomphala. Extracellular application of isobutylmethylxanthine (IBMX) and dibutyryl cyclic AMP showed bursting activity-like firing in the PTZ-sensitive neurons. When 5'-guanylylimidodiphosphate (GNP-PNP) was injected into PTZ-sensitive neurons in the extracellular presence of IBMX and dibutyryl cyclic AMP, bursting activity followed by long-lasting hyperpolarization occurred. Intracellular injection of cyclic AMP into PTZ-sensitive neurons caused hyperpolarization coincident with an increase in intracellular calcium concentration. This increase in intracellular calcium concentration was the same under conditions in which the calcium influx was inhibited by the substitution of extracellular calcium chloride by cobalt chloride. In PTZ-non-sensitive neurons, cyclic AMP-induced bursting activity was not observed. These results suggest that an increase in cyclic AMP provoked bursting activity via an increase in intracellular calcium concentration.

[1]  M. Onozuka,et al.  Intracellular protein changes during pentylenetetrazole induced bursting activity in snail neurons , 1982, Brain Research.

[2]  M. Onozuka,et al.  Behavior of intracellular cyclic nucleotide and calcium in pentylenetetrazole-induced bursting activity in snail neurons , 1983, Brain Research.

[3]  A Sugaya,et al.  Pentylenetetrazol-induced intracellular potential changes of the neuron of the Japanese land snail Euhadra peliomphala. , 1973, The Japanese journal of physiology.

[4]  K. Kajiwara,et al.  Intracellular calcium concentration during pentylenetetrazol-induced bursting activity in snail neurons , 1987, Brain Research.

[5]  R. Stornetta,et al.  Inhibition of sympathetic preganglionic discharges by epinephrine and α-methylepinephrine , 1982, Brain Research.

[6]  Properties of cAMP-induced transmembrane current in mollusc neurons , 1986, Brain Research.

[7]  R Y Tsien,et al.  Neutral carrier ion-selective microelectrodes for measurement of intracellular free calcium. , 1980, Biochimica et biophysica acta.

[8]  R. Meech,et al.  Intracellular calcium injection causes increased potassium conductance in Aplysia nerve cells. , 1972, Comparative biochemistry and physiology. A, Comparative physiology.

[9]  J. Ferrendelli,et al.  Cyclic Nucleotides in Epileptic Brain: Effects of Pentylenetetrazol on Regional Cyclic AMP and Cyclic GMP Levels In Vivo , 1977, Epilepsia.

[10]  M. Onozuka,et al.  Ion shower milling: its application to cell membrane removal. , 1978, Science.

[11]  J. Aldenhoff,et al.  Stimulation of a sodium influx by cAMP in Helix neurons , 1983, Brain Research.

[12]  E. Sugaya,et al.  Intracellular calcium: its release from granules during bursting activity in snail neurons. , 1978, Science.

[13]  M. Onozuka,et al.  Intracellular calcium: its movement during pentylenetetrazole-induced bursting activity. , 1978, Science.

[14]  S. Binkley,et al.  The pineal gland: a biological clock in vitro. , 1978, Science.

[15]  N. I. Kononenko,et al.  The effect of intracellular cAMP injections on stationary membrane conductance and voltage- and time-dependent ionic currents in identified snail neurons , 1983, Brain Research.