Monosynaptic connections between serotonin-containing neurones labelled by 5,6-dihydroxytryptamine-induced pigmentation in the snail Helix pomatia L.

Microelectrophysiological experiments were carried out on in vivo 5,6-dihydroxytryptamine-induced pigment-labelled serotonin-containing neurones of Helix pomatia. Excitatory chemical monosynaptic connections were found between the giant pedal LP3 neurone and several follower cells in the visceral and right parietal ganglia. These neurones have previously been described to be involved in regulation of visceral functions. Monitoring changes in identified monosynaptic connections between pairs of serotonin-containing neurones aids the cellular analysis of behavioural plasticity.