GRIN2B and Tinnitus: However, NR2B protein levels in the IC were significantly decreased in the Spirulina group (0.89±0.08 versus 1.30±0.17, p = 0.014) and in the C-PC group (0.66±0.04 versus 1.30±0.17, p = 0.001), compared with the tinnitus group (Figure 6).