Articles
Authors: AM McMahon ( ) , C Carati ( ) , N Piller ( ) , BJ Gannon ( )
In order to assess the effects of irradiation on lymphatic function, the contraction frequency and maximum and minimum diameters of guinea pig mesenteric collecting lymphatic vessels were measured in vivo 4 hours after 1000 rads of abdominal irradiation. The mean contraction frequency for lymphatics from irradiated guinea pigs (7.6±0.7) was significantly higher than for normals (nonirradiated) (4.7 ±0.7) during an initial control observation period, but there was no difference in maximum or minimum diameter between the two groups during this period. Topical application of 10-4M noradrenaline (NA) significantly increased contraction frequency in both groups;lymph vessel diameter significantly decreased after NA in irradiated, but not in normal guinea pigs. Intravenous infusion of calcium dobesilate (200 mg/kg) caused a significant increase in the contraction frequency of lymphatic vessels in both normal (to 9.4± 1.5) and irradiated (to 9.8±1.2) animals, but diameter was not significantly altered. Thus, lymphatic vessels from irradiated guinea pigs were still responsive to exogenous stimuli 4 hours post-irradiation and were initially pumping more actively than those from normal guinea pigs, presumably in response to radiation-induced edema. They also exhibited a supersensitivity to the vasoconstrictive effects of NA, perhaps due to an alteration of the pacemaker or smooth muscle cells by irradiation.
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How to Cite: McMahon, A. , Carati, C. , Piller, N. & Gannon, B. (1994) “THE EFFECTS OF RADIATION ON THE CONTRACTILE ACTIVITY OF GUINEA PIG MESENTERIC LYMPHATICS”, Lymphology. 27(4).