Melatonin modulates mesenteric blood flow and TNFalpha concentrations after lipopolysaccharide challenge.
OBJECTIVE
To investigate the effect of various doses of melatonin on reduction in mesenteric blood flow (MBF) and increase in tumour necrosis factor alpha (TNFalpha) concentration caused by injection of lipopolysaccharide (LPS).


METHODS
University Hospital, Turkey.


METHODS
Open experimental study.


METHODS
59 Swiss albino mice.


METHODS
Animals were injected with melatonin solvent or 1, 10, 100, or 500 mg/kg melatonin. Ten minutes later control animals were injected with saline, and the experimental group with LPS.


METHODS
Mesenteric blood flow and serum TNFalpha concentration.


RESULTS
In control animals, 100 and 500 mg/kg melatonin reduced MBF. LPS reduced MBF in solvent, 1, and 10 mg/kg melatonin groups. The concentration of TNFalpha was considerably increased in the mice given LPS. Melatonin reduced this response significantly.


CONCLUSIONS
In high doses melatonin directly reduces MBF. It has no protective effect on the LPS-induced decrease in MBF. In lower doses it blocks, but at higher doses reduces, LPS-induced TNFalpha production.
Baykal
A
A
Department of General Surgery, University of Hacettepe, Faculty of Medicine, Ankara, Turkey.
Iskit
A B
AB
Hamaloglu
E
E
Guc
M O
MO
Hascelik
G
G
Sayek
I
I
D000818:Animals; D005260:Female; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D011897:Random Allocation; D012772:Shock, Septic / Q000097:blood; D012997:Solvents / Q000494:pharmacology; D013152:Splanchnic Circulation / Q000187:drug effects* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D008070:Lipopolysaccharides; D012997:Solvents; D014409:Tumor Necrosis Factor-alpha; D008550:Melatonin