ANTIBODY-COATED ELECTRODES FOR DETECTING SOMATIC EXOCYTOSIS OF SOMATOSTATIN-LIKE MATERIAL IN HELIX NEURONS

Immunoelectrodes have been developed which can be used to detect minut e amounts of somatostatin. They were made with electrochemically treat ed glassy carbon fibres coated with anti somatostatin antibodies, Cali bration and various controls were carried out to ensure that the immun oelectrodes responded specifically to the presence of femtomolar somat ostatin. Electrophysiological experiments were performed on anti-somat ostatin immunoreactive neurones in the snails Helix aspersa and H. pom atia. Somatostatin-like material was released in response to sustained firing. The release was measured at the soma, which means that it occ urred in the extrasynaptic area. The finding that the fluorescent dye FM 1-43 was incorporated into somatic vesicles confirmed that exocytos is actually occurred during sustained neuronal firing.