Helix aspersa neurons maintain vigorous electrical activity when co-cultured with intact H. aspersa ganglia

1. Identified neurons from the right parietal lobe of the circumoesophageal ganglion of adult land snails, Helix aspersa, were isolated and placed in primary cell culture. 2. The individual neurons were removed from the right parietal lobe by microdissection without the aid of exogenous enzymes and plated on poly-L-lysine coated coverslip in normal Helix Ringer's solution conditioned with Helix circumoesphageal ganglia. The neurons become firmly attached to the substrate and begin to extend processes within 6 hr. 3. The cells show a dramatic increase in electrical activity when they are co-cultured with intact Helix circumoesophageal ganglia (1 ganglion/ml). Co-cultured neurons have resting potentials between -45 and -110 mV, comparable to in situ, show spontaneous action potential firing and respond to putative neurotransmitters. Heat-treated conditioned media was inactive. 4. When dopamine or serotonin (5-HT) are added, right parietal beating neurons, F14-F16 and F29-F32, (i) show a suppression of action potentials occurrence; (ii) a decrease in action potential amplitude and duration, and (iii) an increase in after-hyperpolarization. 5. Right parietal bursting neuron F1 in culture fire action potentials only in a beating mode. Dopamine addition to F1 suppresses action potential occurrence and causes an increase in action potential after-hyperpolarization, but there is only a small decrease in duration of action potentials and no significant change in action potential amplitude. 5-HT addition to F1 increases the occurrence of action potentials with little or no change in action potential shape. 6. This primary cell culture method is an efficient system for doing biochemical and electrophysiological studies on individual, identified neurons.