AGE-RELATED-CHANGES OF THE NORADRENERGIC AND ACETYLCHOLINESTERASE REACTIVE NERVE-FIBERS INNERVATING THE PIGEON BURSA OF FABRICIUS

Age-dependent changes in the innervation of the pigeon (Columba livia, L.) bursa of Fabricius, from hatching to 120 days of age, were studie d by fluorescence-histochemical and neurochemical methods for demonstr ating noradrenergic and acetylcholinesterase (AChE)-reactive nerve fib res respectively. The distribution of both nerve fibre types was large ly perivascular. Furthermore, a few isolated nerve fiber profiles were observed beneath the bursal epithelium, in the interfollicular septa and in the follicular cortex. No nerve fibre profiles reaching the med ulla of the lymphoid follicles were observed. In addition to nerve fib res, AChE reactive neuron-like cells were encountered within the capsu le and interfollicular septa. AChE reactivity was also found in dendri tic-like cells localized in the cortical and cortico-medullary border. No changes in the density of perivascular noradrenergic innervation w ere noticeable during the ages studied, whereas the density of AChE-re active fibres supplying Vessels reached the adult pattern at 30 days, and then remained unvaried. The density of non-perivascular nerve fibe r profiles, specially the AChE reactive type, increased until 30 days, remained unchanged until 75 days and then increased with aging (90-12 0 days). The interrelationship between the autonomic nervous system an d the immune system is discussed.