Abstract
Abstract: :
Purpose: To investigate the levels of secretoneurin in the human aqueous humor following topical administration of cromycin, vexol, voltaren ophtha and cyclosporin A. Methods: Cataract patients were randomly selected and included in the study. The patients were treated one day before surgery each hour by either cromycin alone as a control or both cromycin and vexol or cromycin and voltaren ophtha or cromycin and cyclosporin A. Aqueous humor was aspirated by paracenthesis before the beginning of surgery and secretoneurin was detected by a highly sensitive radioimmunoassay. Results: The mean concentration of secretoneurin in the cromycin group was 479,36 ± 47,6 fmol/ml, in the group treated with cromycin and vexol 414,16 ± 88,9 fmol/ml, in the group treated with cromycin and voltaren ophtha 511,65 ± 57,9 fmol/ml and in the group treated with cromycin and cyclosporin A 474,24 ± 34,4 fmol/ml. Significance was reached in none of the groups when compared to the cromycin control group but there was a clear tendency of vexol to decrease the concentration of secretoneurin (p=0,057, student's t test). Conclusion: The present results clearly indicate that topical application of vexol tends to decrease secretoneurin in the aqueous humor. This is in agreement with the knowledge that corticosteroids attenuate neurogenic inflammation possibly by decreasing either the synthesis and/or release of neuropeptides. There was no effect seen for voltaren ophtha and for cyclosporin A. This is in contrast to substance P which has been found to be decreased in the aqueous humor following topical administration of another non steroidal antiinflammatory drug, in particular indomethacin (Kieselbach et al. 1993). The lack of effect of cyclosporin A may indicate that this drug does not penetrate the cornea and thus does not affect secretoneurinergic nerves or that this peptide is unresponsive in contrary to another peptide, substance P, which is known to participate in cyclosporin A-induced tear fluid secretion (Yoshida et al., 1999).
Keywords: neuropeptides • aqueous • pharmacology