NORADRENALINE UPTAKE INTO CEREBAL CORTEX: A HISTOCHEMICAL STUDY

Abstract— Experiments are reported which illustrate, by means of the histochemical technique of F alck and H illarp , the distribution of noradrenaline in the cerebral cortex of the rat after topical application to small areas of the pia mater. The noradrenaline is accumulated in a system of fibres and cells in the cortex by a mechanism which can be blocked by desmethylimipramine, amphetamine and phenoxybenzamine, but not by reserpine. In sections from untreated cerebral cortex the fibres contain enough noradrenaline to be visible after histochemical preparation but the cells do not. However, due to the high concentrations of noradrenaline used, the specificity of the uptake into cell bodies must remain in doubt.     

Statocysts of medusae and evolution of stereocilia

Ectodermal sensory cells of the statolith each bear one nonmotile kinocilium, and in some hydromedusae bear stereocilia which are defined as distinct from microvilli by having fibrillar rootlets. The progressive elaboration of stereocilia can be traced. A hypothesis in which jellyfish statocysts evolve from vibration receptors avoids the difficulty of the uselessness of incipient gravity organs. Comparative study suggests that the kinocilium or its basal body is the transducer.