Adrenergic innervation and vascular patterns in caine adipose tissue

Abstract

To visualize blood vessels, canine adipose tissue (in subcutis, mesentery, and omentum) was perfused with a silicone elastomer containing a fluorescent material, Rhodamine B. Adrenergic nerve fibres were made fluorescent by formaldehyde treatment of stretch preparations by the method of Falck and Hillarp. An extensive capillary network surrounding each adipocyte was found. In the mesentery the adipocytes appear to be located in the venous section of the microvasculature rather than on the arterial side. This indicates that adipocytes are localized to vessels with the highest permeability. A rich perivascular plexus of fluorescent varicose nerves could be seen around the arteries and veins. Nerve fibres could also be found between adipocytes. However, the pattern of distribution was not as regular as that of the microvasculature. In some areas no adrenergic nerve fibres could be identified around the adipocytes. This might indicate that there are two pools of adipocytes in a tissue, one which is innervated by adrenergic fibres and responds with increased lipolysis to sympathetic nerve activity and another which does not.