Cytological and biochemical studies on chromaffin cells in the head kidney of Gasterosteus aculeatus (Teleostei, Gasterosteidae).

Adrenal chromaffin cells in the head kidney of the stickleback Gasterosteus aculeatus were examined by ultrastructural analysis and determination, by HPLC, of the catecholamine content (adrenaline, noradrenaline, and dopamine). Chromaffin cells are characterized by the presence of membrane-bound vesicles and two cell types were identified: (i) those with vesicles containing a strongly electron-dense core; and (ii) those with vesicles that are completely electron lucent or containing smaller and less-dense granules. HPLC analysis revealed the presence of adrenaline and noradrenaline in both right and left head kidneys. Dopamine was not detected. Cytological and biochemical data suggest that the cells with electron-dense granules contain noradrenaline and those with electron-lucent vesicles contain adrenaline.