Table 2.
Vessel properties
| Vessel order | Arterioles |
Capillaries |
Venules V | ||||
|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | S | I | D | ||
| Number of series (n rats) | 17 (16) | 17 (13) | 29 (22) | 74 (33) | 29 (18) | 18 (12) | 12 (12) |
| Baseline diameter (μm) | 28.1 ± 1.0 | 10.5 ± 0.8 | 7.6 ± 0.4 | 5.5 ± 0.1 | 4.8 ± 0.1 | 5.4 ± 0.2 | 39.7 ± 3.1 |
| Dilation (%) | 7.5 ± 0.7 | 5.0 ± 0.9 | 2.7 ± 0.4 | 1.8 ± 0.2 | 2.3 ± 0.2 | 1.9 ± 0.3 | 1.1 ± 0.2 |
| % responding | 100.0 | 91.7 | 85.7 | 75.7 | 93.1 | 61.1 | 100.0 |
Vessel orders 1, 2, and 3 are the first, second, and third branches off the central retinal artery. D, Deep layer capillaries; I, intermediate layer capillaries; S, superficial layer vessels of order 4 and higher, defined as capillaries; V, venules are the first branch off the central retinal vein. Dilation indicates mean dilation during the first 4 s of the stimulus, and % responding indicates the percentage of series that showed stimulus-evoked dilations that rose at least 3 SDs above baseline.