Monoamine oxidase in sympathetic ganglia of the cat.

Abstract

AbstractThe monoamine oxidase (MAO) activity of sympathetic ganglia and isolated ganglion cells of the cat has been studied by a micromodification of the radiochemical method of McCaman et al. (1965a) using (14C) tyramine. The superior cervical, stellate and coeliac ganglia showed a high MAO activity, the coeliac having almost twice the activity of the others. The 6th and 7th lumbar and the 1st sacral ganglia showed lower and approximately the same activity. No significant change in MAO activity could be detected in the lumbo sacral ganglia three to four weeks after denervation.The 7th lumbar ganglion was used for the single cell experiments. 73 per cent of the ganglion cells had measurable MAO activity with a range from 1 to 41 moles of product x10‐12/hr (mean ±S.E. =5.5±0.57). The results support the previous suggestion that the sympathetic ganglia of the cat contain two distinct cell populations; firstly, a cholinergic population, representing in L7 about 10–15 per cent of the ganglion cells, characterized by the presence of ChAc, high concentrations of AChE and the absence of monoamine fluorescence and MAO activity; secondly, an adrenergic population, about 73–88 per cent of the ganglion cells, which exhibits fluorescence for noradrenaline and MAO activity, contains low or moderate AcChE and no measurahle ChAc activity.