Local substances regulating cochlear blood flow

The regulation of cochlear lateral wall blood flow was investigated in rats using histochemistry, immunohistochemistry and transmission electron micro scopy. The contractile protein, tropomyosin (TM) was localized in the peric yte around the vessels of spiral ligament but little was seen around strial capillaries. Prostaglandin I-2 (PGI(2)) is a vasodilatory substance produc ed by PGI(2) synthase (PGI(2)S), which is present in the endothelium of the vessels of spiral ligament but not much is present around strial capillari es. Endthelial nitric oxide synthase (eNOS) was present in the endothelium of both the vessels of spiral ligament and strial capillaries. These findin gs indicate that the blood flow of the cochlear lateral wall is regulated m ainly in the spiral ligament by locally produced substances and that strial blood flow is not significantly regulated by pericytes responsible for enl argement or constriction of capillaries.