A comparative study of adrenergic innervation of the spleen in guinea-pigsand chickens

A comparative morphological study of adrenergic innervation of the spleen i n guinea-pigs and chickens using the glyoxylic acid histofluorescence metho d has revealed that, in both cases, the adrenergic nerve components enter t he spleen, accompanied with arteries and, in form of the plexiform perivasc ular bundles, they pass through the organ as far as their terminal parts. T he thinner nerve branches and solitary varicose fibres, extending away from these perivascular plexuses, form a rich network lining in the peripheral side of the vascular media (so-called "adventitial plexus"); in guinea-pigs . They are also present in a remarkable number in fibrous trabeculae, in th e marginal zone of periarteriolar lymphatic sheath (PALS), in the perifolli cular topography and, sporadically, in sinuses and cords of the red pulp. T he perifollicular nerve fibres in chickens are more abundantly represented than those in guinea pigs. Innervation of fibrous capsule of the organ in a lmost the same in both animals although the fibrous trabecular system is in sufficiently developed in chickens. In both cases, innervation of most of t he venous trunks appears to be surprisingly abundant. The microscopic findi ngs are consistent with the view that adrenergic nerve components in the sp leen participate in the regulation of arterial motility as well as in the r egulation of the microenvironment of the organ's own parenchyma.