[Changes in systemic and local vascular reactivity in hemorrhagic shock and the therapeutic effect of delta opioid receptor antagonist ICI174,864].
OBJECTIVE
To investigate the changes in systemic and local vascular reactivity following hemorrhagic shock of different severity and the therapeutic effect of alpha opioid receptor antagonist ICI174,864.


METHODS
Fifty-six Wistar rats were used in two experiments. In experiment I, 32 rats were equally divided into sham operation group, 1 hour, 2 hours and 3 hours hypotension groups. In the latter groups, rats were bled to a mean arterial blood pressure (MAP) of 40 mm Hg (1 mm Hg=0.133 kPa) and maintained at this level for 1, 2, 3 hours, respectively. The pressor response of blood pressure and the contractile response of superior mesenteric artery (SMA) to norepinephrine(NE, 3 ug/kg) were observed after shed blood was reinfused. In experiment II, 24 rats were divided into shock control, ICI174,864 0.5 mg/kg and 1.0 mg/kg groups. The response of blood pressure and SMA contractility to NE (3 microg/kg) were observed at 1, 2, and 4 hours after ICI174,864 administration.


RESULTS
Following hemorrhagic shock, the systemic and local (SMA) vascular responsiveness was significantly decreased significantly and it was time dependent. Shed blood reinfusion alone did not restore the decreased vascular reactivity. ICI174,864 improved the decreased vascular reactivity in dose-dependent manner.


CONCLUSIONS
Hemorrhagic shock can induce systemic and local vascular hyporeactivity. The decreased vascular reactivity is closely associated with the severity and duration of shock. Loss of systemic vascular reactivity parallels to that of the regional vessel. delta opioid receptor antagonist ICI174,864 has some beneficial effect in improving vascular hyporeactivity.
Liu
Liang-ming
LM
State Key Laboratory of Trauma, Burns and Combined Injury, The Second Department of Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042, China.
Li
Ping
P
Diao
You-fang
YF
Zhou
Xue-wu
XW
Zhou
Rong
R
Liao
Zi-fu
ZF
Tian
Kun-lun
KL
Liu
Jian-cang
JC
D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects / Q000503:physiopathology; D009638:Norepinephrine / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*; D012771:Shock, Hemorrhagic / Q000503:physiopathology*; D014661:Vasoconstriction / Q000187:drug effects
D017465:Receptors, Opioid, delta; D004743:Enkephalin, Leucine; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine; D009638:Norepinephrine