In vivo release of interleukin-1 beta into hypothalamic extracellular fluid in rats: effects of repeated sampling.
Interleukin-1 beta (Il-1 beta) concentrations in extracellular fluid (ECF) withdrawn at 10-min intervals through a push-pull cannula (PPC) located in the hypothalamus were studied in freely behaving male rats for 1 h at 24 and 72 h and again at 7 days after PPC implantation. Il-1 beta concentrations in ECF were similar in the latter. However, when ECF was sampled at 3 h and again 7 days after PPC implantation, Il-1 beta concentrations were greatly elevated at 7 days when compared to all other intervals. These results demonstrate how the relationships between Il-1 beta measured in ECF and the conditions of measurement appear to be integral parts of a whole intracerebral system: cytokine concentrations appear to be inextricably bound to intrahypothalamic conditions created by the sampling device presence and frequency of use.
Phelps
C P
CP
Department of Anatomy, University of South Florida, College of Medicine, Tampa 33612-4799, USA.
Sahu
A
A
Oliver
J
J
Ma
X L
XL
Kalra
P S
PS
Kalra
S P
SP
Menzies
R A
RA
Chen
L
L
Denker
M
M
Horvath
E
E
D000818:Animals; D002408:Catheters, Indwelling; D005110:Extracellular Space / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007375:Interleukin-1 / Q000378:metabolism*; D008297:Male; D010477:Perfusion; D051381:Rats
D007375:Interleukin-1