H. Yamane et al., NITRIC-OXIDE SYNTHASE AND CONTRACTILE PROTEIN IN THE RAT COCHLEAR LATERAL WALL - POSSIBLE ROLE OF NITRIC-OXIDE IN REGULATION OF STRIAL BLOOD-FLOW, Hearing research, 108(1-2), 1997, pp. 65-73
The present study demonstrated by histochemical and immunohistochemica
l methods that NADPH diaphorase reactivity, endothelial nitric oxide s
ynthase (eNOS)-like immunoreactivity, and tropomyosin-like immunoreact
ivity, were located within the rat cochlear lateral wall. Both NADPH d
iaphorase reactivity and eNOS-like immunoreactivity were found mainly
in the endothelium of the strial capillaries (ESC) and that of the ves
sels of the spiral ligament (ESL). These reaction products appeared to
be somewhat more common in the ESC than in the ESL. On the other hand
, tropomyosin-like immunoreactivity was localized in tissues outside t
he endothelium and its intensity was greater in the ESL than in the ES
C. These findings suggest that nitric oxide (NO) produced by eNOS may
play a role in regulating the blood flow of the cochlear lateral wall.
In addition, NADPH diaphorase reactivity, eNOS-like immunoreactivity,
and tropomyosin-like immunoreactivity showed different patterns of di
stribution between ESC and ESL. This suggests that in these two sites
blood circulation is controlled by NO through two different mechanisms
that are suitable for regulating strial blood flow.