Epileptogenic drugs in a model nervous system: electrophysiological effects and incorporation into a phospholipid layer.

Mechanisms of epileptiform activity in a model nervous system (buccal ganglia of Helix pomatia) are presented. The ganglia contain the identified giant neurons B1 through B4. For epileptiform activity, pentylenetetrazol (1 mmol/L to 40 mmol/L) or etomidate (12.

Block of spontaneous termination of paroxysmal depolarizations by forskolin (buccal ganglia, Helix pomatia).

Effects of cAMP-activated protein kinases (PKA) on epileptic activity are at present studied in a model nervous system. Identified neurons in the buccal ganglia of the snail Helix pomatia were recorded with intracellular microelectrodes in a continuously perfused experimental chamber. Epileptiform activity appeared regularly in neuron B3 when the saline contained pentylenetetrazol (20-40 mM).

Continuous increase of epileptogenic effects following application of proteolytic enzymes (buccal ganglia of Helix pomatia).

Epileptic activity of neurons consists of paroxysmal depolarization shifts (PDS) which can be induced presumably in any nervous system by application of an epileptogenic drug. The spontaneous appearance of epileptic activity, however, is based on a largely unknown process which increases susceptibility to epileptic activity (seizure susceptibility in man). It is presently shown that the treatment of ganglia with proteolytic enzymes (Pronase) decreases the effective concentration of epileptogenic drugs, i.

Pacemaker potentials are the physiologic basis of epileptiform activity in the buccal ganglia of Helix pomatia.

Mechanisms of epileptic activity in nervous systems were studied using the identified neurons B1 through B4 in the buccal ganglia of the snail Helix pomatia as a model system. Activities were recorded with intracellular microelectrodes. Epileptiform activity was induced by bath application of an epileptogenic drug (pentylenetetrazol: 1 mM to 40 mM, or etomidate: 0.

Epileptogenicity and epileptic activity: mechanisms in an invertebrate model nervous system.

Epileptic seizures are based on paroxysmal depolarization shifts (PDS) which are synchronized in many neurons. Mechanisms underlying PDS and seizures are still not understood. The present review is based on studies using the buccal ganglia of the snail Helix pomatia as a model nervous system.