SALIVARY ALPHA-AMYLASE LEVELS MAY CORRELATE WITH CENTRAL SEROUS CHORIORETINOPATHY ACTIVITY.

PURPOSE: To investigate and compare the salivary alpha-amylase (sAA) activity as an indicator of the sympathetic activity and stress response in patients with central serous chorioretinopathy (CSC) and healthy control subjects. METHODS: Prospective multicenter case series, including 80 CSC patients and 88 healthy control subjects. Central serous chorioretinopathy status was classified as either active or inactive, depending on the presence of subretinal fluid on optical coherence tomography. Salivary samples were collected in the morning from patients and control subjects of the main cohort and at midnight for the additional cohort. Salivary alpha-amylase activity was determined in all patients and control subjects. RESULTS: Morning sAA activity was significantly higher in patients with active CSC compared with inactive CSC (P = 0.049) and to healthy control subjects (P = 0.012). There was no significant difference in sAA activity between patients with inactive CSC and control subjects (P = 1.0). Nocturnal sAA activity did not show any significant difference between patients with active CSC and either inactive CSC or control subjects (P = 0.139). CONCLUSION: Morning sAA activity is increased in patients with active CSC, although diurnal rhythmicity is preserved. Measurement of sAA is easy to perform and might be an eligible tool to further investigate the relation between stress and CSC.

Low concentrations of ethanol but not of dimethyl sulfoxide (DMSO) impair reciprocal retinal signal transduction.

BACKGROUND: The model of the isolated and superfused retina provides the opportunity to test drugs and toxins. Some chemicals have to be applied using low concentrations of organic solvents as carriers. Recently, E-/R-type (Cav2.3) and T-type (Cav3.2) voltage-gated Ca(2+) channels were identified as participating in reciprocal inhibitory retinal signaling. Their participation is apparent, when low concentrations of NiCl2 (15 µM) are applied during superfusion leading to an increase of the ERG b-wave amplitude, which is explained by a reduction of amacrine GABA-release onto bipolar neurons. During these investigations, differences were observed for the solvent carrier used. METHODS: Recording of the transretinal receptor potentials from the isolated bovine retina. RESULTS: The pretreatment of bovine retina with 0.01 % (v/v) dimethylsulfoxide did not impair the NiCl2-mediated increase of the b-wave amplitude, which was 1.31-fold ± 0.03 of initial value (n = 4). However, pretreatment of the retina with the same concentration of ethanol impaired reciprocal signaling (0.96-fold ± 0.05, n = 4). Further, the implicit time of the b-wave was increased, suggesting that ethanol itself but not DMSO may antagonize GABA-receptors. CONCLUSION: Ethanol itself but not DMSO may block GABA receptors and cause an amplitude increase by itself, so that reciprocal signaling is impaired.