Articles

CONTRACTILE PROPERTIES OF LYMPHATICS FROM THE HUMAN LOWER LEG

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Abstract

Lower leg lymphatics, taken from seven volunteers, were investigated in vitro. Isometric contractions were induced by noradrenaline, 5-hydroxytryptamine (5-HT), prostaglandin F_2α (PGF_2α), and the thromboxane A₂ (TXA₂)-mimetic U-44069. Noradrenaline induced phasic contractions in 6 of 7 segments. The amplitude of the contractions were up to 100% of a previous K⁺ (124mM)-induced contraction and the frequency at 10^-6M of noradrenaline was 5-13 min^-1. These contractions were unaffected by propranolol (10^-6M), but they were abolished by phentolamine (10^-6M). Noradrenaline had an E_max (tonic contraction) of 7% of the K+ (124mM) contraction (n = 7) and the pEC₅₀-value was 6.9 (n = 3). The corresponding values for 5-HT were 21% (n = 5) and 6.4 (n = 3). PGF_2α elicited contractions in all segments investigated (E_max = 87%, pEC₅₀ = 5.8, n = 5). U-44069 had high contractile capacity and potency in all investigated segments (E_max = 137%, pEC₅₀ = 8.9, n = 7). Phasic contractions were elicited also by 5-HT, PGF_2α and U-44069. Compared to earlier studies of human peripheral lymphatics, these results show that there are regional differences in susceptibility to these vasoactive agents.

How to Cite:

Sjoberg, T. & Steen, S., (1991) “CONTRACTILE PROPERTIES OF LYMPHATICS FROM THE HUMAN LOWER LEG”, Lymphology 24(1), 16-21.