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- Title
Exercise training attenuates anaphylactic venoconstriction in rat perfused liver, but does not affect anaphylactic hypotension in conscious rats.
- Authors
Cui, Sen; Shibamoto, Toshishige; Zhang, Wei; Kurata, Yasutaka; Kashimura, Osamu; Miyamae, Shunichi
- Abstract
1. Exercise training attenuates circulatory shock due to haemorrhage, endotoxin or heatstroke. However, it remains unknown whether exercise training attenuates anaphylactic shock. Hepatic venoconstriction is involved in rat anaphylactic hypotension. In the present study, we determined the effects of exercise training on both anaphylaxis-induced segmental venoconstriction in rat perfused livers and systemic anaphylaxis in conscious rats. The role of nitric oxide (NO) in the effect of exercise on the venoconstriction of perfused livers was also examined. 2. Rats were subjected to running training on a motorized treadmill for 4 weeks. Two weeks prior to the anaphylaxis experiment, Sprague-Dawley rats were actively sensitized with the antigen ovalbumin. In isolated livers perfused portally with blood, the portal venous pressure (Ppv) and sinusoidal pressure were measured to determine the pre- and post-sinusoidal resistances (Rpre and Rpost, respectively). In conscious rats, systemic arterial pressure (SAP) and Ppv were determined. 3. In the perfused livers of sedentary rats, antigen administration led to a predominant presinusoidal constriction, as evidenced by 4.6- and 1.7-fold increases in Rpre and Rpost, respectively. The anaphylaxis-induced increase in Rpre was significantly attenuated by 24% by exercise training. Inhibition of NO synthase with NG-nitro-l-arginine methyl ester (100 μmol/L) 10 min prior to the injection of antigen enhanced anaphylactic venoconstriction, but did not alter the effect of exercise training on the increase in Rpre. In contrast, exercise training did not attenuate either anaphylactic hypotension or portal hypertension in conscious rats. 4. In conclusion, exercise training attenuates the anaphylaxis-induced presinusoidal constriction in rat isolated perfused livers, independent of NO production. However, this action is not evident in conscious rats and exercise training does not affect anaphylactic hypotension in conscious rats.
- Subjects
ANAPHYLAXIS; VASODILATION; LIVER; VENOUS pressure; NITRIC-oxide synthases; BLOOD circulation disorders; LABORATORY rats; TREADMILLS
- Publication
Clinical & Experimental Pharmacology & Physiology, 2010, Vol 37, Issue 9, p889
- ISSN
0305-1870
- Publication type
Article
- DOI
10.1111/j.1440-1681.2010.05401.x