Figure 5.

Phosphorylation of α4/β2 nAChRs in vivo following nicotine exposure. nAChRs were immunoprecipitated from mouse brain homogenates using a monoclonal antibody raised against the α4 subunit, isolated by gel electrophoresis, and bands corresponding to the α4 and β2 subunits were excised and subjected to mass spectrometry. Phosphorylation level was normalized to total subunit protein. Phosphorylation of S491, S543, and S563 on the α4 subunit was detected in brain homogenates from saline treated mice. (a) Following acute nicotine exposure in vivo, phosphorylation of S444 and S448 was significantly increased, whereas phosphorylation of S470 was significantly decreased to undetectable levels. (b) Following chronic exposure to nicotine, no significant differences from baseline phosphorylation were observed in the α4 subunit. No phosphorylation of the β2 subunit was detected. * p < 0.05. Error bars represent standard error of the mean; n = 10/condition.