Release of nitric oxide by N-nitropyrazoles in rabbit lacrimal gland cell culture.

Purpose: In order to prove the effects of N-nitropyrazoles to increase ocular blood flow and to facilitate retinal function after ischemia are due to nitric oxide (NO) release, eleven N-nitropyrazoles which are known NO donors were used to test their ability to produce NO in rabbit lacrimal gland (RLG) cell cultures.

Methods: Nitropyrazoles (0.3-3 microg/ml) were added into RLG cell culture and the NO produced was determined with nitrate-nitrite colorimetric assay.

Results: All nitropyrazoles (11 compounds) tested produced NO in various degrees with the highest degree by 13 fold over control (DN-5) and the lowest level by only 2.8 fold over control (DN-7).

Conclusion: The results indicated that NO is involved in ocular blood flow increase and retinal function recovery after ischemia by N-nitropyrazoles. However, there is no potency relationship between in vitro data and in vivo data, which is understandable because the experimental environments are different.