MONITORING OF NICOTINE IMPACT IN MICROLYMPHATICS OF RAT MESENTERY WITH TIME-RESOLVED MICROSCOPY

Abstract

The aim of the study was to evaluatenicotine-induced microlymphatic responsesin rat mesentery in vivo with time-resolvedtransmission microscopy. Male Fisher ratsweighing 150-200g were used in allexperiments. The experiments revealed thatchanges of lymphatic function under directnicotine impact (continuous topical applicationof nicotine in the concentration rangesof 0.001 mM, 10 mM and 100 mM for 15minutes) were dose- and time-dependent.A nicotine dose of 10mM caused an immediateshort-term constriction of 100% oflymphangions. At the highest concentrationof nicotine (100 mM), similar constriction aswell as inhibition of lymph flow, local stableconstriction of lymph microvessels, stasis inblood microvessels, and disturbances ofrespiration were observed. Application ofchronic nicotine (0.23 ml from a 10 mMsolution) injection for 14 days via a miniosmoticpump did not substantially changethe function of lymphatic and blood microvessels.Our data show for the first time thatthe acute effect of nicotine is accompanied bysignificant changes in microlymphaticfunction. We conclude that the observedeffects are due to the direct action of nicotineon lymphatics. The mechanism by whichnicotine induces this response remains to beinvestigated further.