Catecholamines in non-neural cells of the CNS: A possibility

Abstract

Publisher Summary This chapter elaborates the catecholamines in non-neural cells of the CNS. The non-neural nature of some catecholamine-containing cells in the brain may contribute to the problems encountered in determining the physiological role of these compounds and to the controversy regarding dopamines role in gonadotrophin secretion. The small dopamine cells of the arcuate nucleus (AN) are at best atypical neurons in that they do not form synapses. That is, using either the standard gluteraldehyde-Os04 procedure or the ethanolic-phosphotungstic acid stain, no synaptic profiles were observed in median eminence either between axon and axon, or between axon and dendrite. The efferent cell processes of AN, appear to terminate adjacent to perivascular spaces. The situation in the AN can be contrasted with the substantia nigra-corpus striatum dopaminecontaining neurons which do form morphological synapses. There is the extreme resistance of AN dopamine to the depleting effect of 6-hydroxy-dopamine. In experiments involving chronic third ventricle cannulation in rats, high doses of 6-OHDA delivered directly into the third ventricle reduced hypothalamic norepinephrine levels to less than 10% of normal.