Changes in the Superoxide Production and Other Macrophage
Functions Could Be Related to the Mortality of Mice with
Endotoxin-Induced Oxidative Stress
Y. WONDMIKUN, T. SOUKUP1, G. ASMUSSEN2
Department of Physiology, Gondar College of Medical
Sciences, Gondar, Ethiopia, 1Institute of
Physiology, Czech Academy of Sciences, Prague, Czech
Republic and 2Carl-Ludwig-Institute of
Physiology, University of Leipzig, Leipzig, Germany
Received September 2, 2002
Accepted November 29, 2002
Summary
The effects of lyotropic (swelling) anions (Cl-,
Br-, NO3-
and I-) on contractile properties of fast-twitch extensor digitorum
longus (EDL) and slow-twitch soleus (SOL) muscles were
investigated in vitro at 20 °C and 35 °C. Isolated muscles
bathed in anionic Tyrode solution were stimulated directly and
isometric single twitches and fused tetanic contractions were
recorded. In a Cl- Tyrode solution a decrease of the bathing
temperature led to a cold potentiation of the twitch tension
(Pt) in EDL muscles, however, to a cold depression in SOL
muscles, in both muscles combined with a prolongation of
contraction (CT) and half relaxation (HRT) times. The extent and
order of the potentiating effect of lyotropic anions on the Pt,
CT and HRT in EDL and SOL were quite similar and increased in
the order: Cl-<
Br- < NO3- <
I-. Since the lyotropic anions did
not influence tetanic tensions, the twitch-tetanus ratio (TTR)
was increased in NO3- and
I- solutions. All effects of the
anions were rapidly and completely reversed in both muscles when
the test solution was replaced by the normal one. The
temperature decrease caused no significant alteration in the potentiation capacity of the anions or in the kinetics of their
action and reversibility.
Key
words
Slow and fast muscles • Contractile properties • Twitch
potentiation • Lyotropic anions • Temperature • Rat
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requests
Dr. T. Soukup, Institute of Physiology, Czech Academy of
Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic, fax:
+420 294 442 488, e-mail:
tmsoukup@biomed.cas.cz
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