Significant developments in gastropod endocrinology since 1969 are reviewed.
The anatomy of the CNS, distribution of nerves and the general plan of the vascular system in Deroceras reticulatu m is described.
The central ganglia are encased in a thick perineural sheath, a matrix of collagen in which muscle fibres, blood vessels, granular cells, pigment cells and vesicular cells are embedded. The fine structure of the blood vessels supplying the CNS suggests that metabolic requirements reach the neurones by diffusion from these vessels.
Dorsal Body tissue (DBT) occurs on the cerebral ganglia and intercerebral commissure as well as other parts of the CNS. Synaps-like contact between neurosecretory axons and DBT was not found, but the close relationship with the blood system, suggests secretory material may be liberated directly into the blood.
Distinct groups of possible neurosecretory neurons were identified in the cerebral, parietal and visceral ganglia, but specialised neurohaemal areas were not found. Axons containing large numbers of elementary granules were observed in the perinueral sheath, but axons with swollen ends or evidence of exocytosis was not found. The presence of possible neurosecretory axons close to capillaries and blood spaces suggests release of neurosecretory
material into the blood can take place easily.
During investigation of the CNS a tissue was discovered attached to arteries arising from the cephalic arborescence. It appeared glandular, lacked ducts and was provisionally named the arterial gland. Electron probe microanalysis revealed an accumulation of copper within the arterial gland, but
immunoelectrophoresis performed using rabbit antiserum to H. aspersa haemocyanin. and homogenised arterial glands gave negative results.
The arterial gland in D. reticulatu m contains secretion throughout reproductive development. Its size is extremely variable between individuals, but neither size nor histology could be related to reproductive development. Tissue similar to the arterial gland of A.reticulatus was found in four other gastropod species.