LOCALIZATION AND HISTOLOGY OF THE MEDIAL NEUROSECRETORY-SYSTEM OF THEVENA-CAVA OF SEPIA-OFFICINALIS L

The pericaryal area of the neurosecretory system of the vena cava (NSV ) system of Sepia officinalis is located with serial sections outside the cephalic cartilage approximate 1 mm anteriad of the visceral lobe. It consists of small pericarya with nuclei measuring 3 - 6 mum in dia meter. The axons of the visceral nerves are 1 - 8 mum wide, those of t he NSV system are 10 - 1600 nm diameter. Surrounded by endoneuria they run side by side up to the vena cava. By staining for neurosecretion Light Green Cells and Yellow Cells could be proved in the NSV system. Acetylcholinesterase is missing in the NSV system but catecholamines w ere found. Two types of vesicles occur in the pericaryal area: Light d ense-cored vesicles with aminergic contents and dark dense-cored vesic les. This type of vesicles indicates the presence of neuropeptides.