Enterochromaffin properties of granular cells in the heart of the snails Helix aspersa and Strophocheilus oblongus

• 1.

  1. Specific granular cells were found in the heart, mantle and subesophageal ganglia of the snails Helix aspersa and Strophocheilus oblongus.

• 2.

  2. Histochemical methods for the demonstration of enterochromaffin granules gave positive results in these cells.

• 3.

  3. Differential osmium reduction by nerves in these hearts showed two kinds of fibres: osmiophilic and non-osmiophilic nerves and gives histological evidence of a double innervation (inhibitory and stimulatory fibres) to the snail heart.

• 4.

  4. Osmiophilic endings are reported in the ventricle and auricle and are shown to end very close to the granular cells.

• 5.

  5. No neurosecretory-staining material could be traced along nerves in these hearts.

• 6.

  6. One large bipolar neuron is described in these hearts.

• 7.

  7. Histological preparations of the heart of Strophocheilus oblongus that had long been stimulated through its cardiac nerve show a release of the granular content in the cells and disclose stages of a secretory cycle. It is suggested that these cells are glandular tissue and perform a hormonal function.