Microvascular flow and tissue Po-2 in skeletal muscle of chronic reduced renal mass hypertensive rats

This study determined whether arteriolar blood flow, capillary red blood ce ll (RBC) velocity, capillary hematocrit (Hct(cap)), and tissue Po-2 are alt ered in cremaster muscles of rats with chronic reduced renal mass hypertens ion (RRM-HT) relative to normotensive rats on high- or low-salt (NT-HS vs. NT-LS) diet. The blood flow in first- through third-order arterioles was no t different between NT and HT rats, either at rest or during maximal relaxa tion of the vessels with 10(-4) M adenosine. Capillary RBC velocity was sim ilar between the groups at rest but was elevated in RRM-HT and NT-HS rats d uring adenosine superfusion. Hct(cap) was reduced at rest in RRM-HT and NT- HS rats compared with NT-LS and was reduced in RRM-HT rats during adenosine -induced dilation. Tissue Po-2 was reduced in RRM-HT and NT-HS rats compare d with NT-LS rats during control conditions and was lower in RRM-HT than in NT-LS rats during adenosine-induced dilation. These results indicate that both RRM-HT and chronic exposure of normotensive rats to a high-salt diet l ead to reduced tissue oxygenation, despite the maintenance of normal arteri olar blood flow.