Background: Increasing facts demonstrated the occurrence of sensory gating defects in schizophrenic sufferers, which had relation to the weakening of P50 response inhibition and had association with α7 nicotinic acetylcholine receptor (α7nAChR). Nevertheless, as a noncompetitive antagonist of α7nAChR, Kynurenic acid (KYNA) cannot cross the blood-brain barrier (BBB). In contrast, Kynurenine (KYN), as a precursor of KYNA metabolism, is capable of crossing the BBB. The exploration focused on investigatating the relation of the serum KYN level with P50 among first-episode patients with schizophrenia (FEPS).
Methods: In the exploration, measurement of P50 sensory gating was conducted among 82 FEPS and 73 healthy controls (HC). Positive and Negative Syndrome Scale (PANSS) was used for assessing the psychopathology; and liquid chromatography-tandem mass spectrometry was utilized for measuring the the serum KYN level. Spearman rank correlation coefficient was used to test the correlation between P50 index and serum KYN level and PANSS score. Pearson correlation coefficient was used to test the correlation between serum KYN level and PANSS score.
Results: The serum KYN levels[(251.46 ± 65.93) ng/ml vs. (320.65 ± 65.89) ng/ml, t = -6.38, p < 0.001], S1 amplitude [ (2.88(1.79, 3.78) μV vs. 3.08(2.46, 4.56) μV , Z = -2.17, p =0.030] and S1 minus S2 amplitude [1.60(0.63, 2.49) μV vs. 1.92(1.12, 2.93) μV , Z = -2.23, p = 0.026] in FEPS were apparently lower than those in the HC. An obviously inverse correlation was seen between S1 minus S2 amplitude and the serum KYN levels (r = -0.32, p = 0.004) in the FEPS.