Antibody-coated electrodes for detecting somatic exocytosis of somatostatin-like material in Helix neurones

Abstract

Immunoelectrodes have been developed which can be used to detect minute amounts of somatostatin. They were made with electrochemically treated glassy carbon fibres coated with anti-somatostatin antibodies. Calibration and various controls were carried out to ensure that the immunoelectrodes responded specifically to the presence of femtomolar somatostatin. Electrophysiological experiments were performed on anti-somatostatin immunoreactive neurones in the snails Helix aspersa and H. pomatia. Somatostatin-like material was released in response to sustained firing. The release was measured at the soma, which means that it occurred in the extrasynaptic area. The finding that the fluorescent dye FM 1–43 was incorporated into somatic vesicles confirmed that exocytosis actually occurred during sustained neuronal firing.