PURPOSE: To determine amounts and biochemical characteristics of substance P-like immunoreactivity (SPLI) in tears of normal human subjects. METHODS: Forty-three healthy subjects (16 males and 27 females; age range, 17-80 years) participated. Ten microliters of unstimulated tears were collected with a micropipette from one eye of all subjects. Tear samples were partially purified by C-18 cartridges. SPLI concentrations in purified samples were measured by enzyme immunoassay (EIA). For biochemical characterization of SPLI, tear extracts were fractionated by high-performance liquid chromatography (HPLC). Each fraction then was subjected to EIA. To determine the metabolism of substance P in tears, synthetic substance P was incubated in medium containing pooled tears and then analyzed by HPLC with the detector set at a 210-nm wavelength. RESULTS: The SPLI concentration in normal human tears was 306.0 +/- 96.5 pg/mL (mean +/- SD; range, 148-555 pg/mL). SPLI did not significantly vary by age or gender. HPLC analysis indicated that SPLI in tears consisted of five different substances and that substance P was converted to several fragments, including SP(8-11) by enzymes present in tears. CONCLUSIONS: Substance P, a normal component of human tears, presumably is released from the nerve endings in the ocular surface and converted to fragments by degradative enzymes in tears.
PURPOSE: To determine amounts and biochemical characteristics of substance P-like immunoreactivity (SPLI) in tears of normal human subjects. METHODS: Forty-three healthy subjects (16 males and 27 females; age range, 17-80 years) participated. Ten microliters of unstimulated tears were collected with a micropipette from one eye of all subjects. Tear samples were partially purified by C-18 cartridges. SPLI concentrations in purified samples were measured by enzyme immunoassay (EIA). For biochemical characterization of SPLI, tear extracts were fractionated by high-performance liquid chromatography (HPLC). Each fraction then was subjected to EIA. To determine the metabolism of substance P in tears, synthetic substance P was incubated in medium containing pooled tears and then analyzed by HPLC with the detector set at a 210-nm wavelength. RESULTS: The SPLI concentration in normal human tears was 306.0 +/- 96.5 pg/mL (mean +/- SD; range, 148-555 pg/mL). SPLI did not significantly vary by age or gender. HPLC analysis indicated that SPLI in tears consisted of five different substances and that substance P was converted to several fragments, including SP(8-11) by enzymes present in tears. CONCLUSIONS:Substance P, a normal component of human tears, presumably is released from the nerve endings in the ocular surface and converted to fragments by degradative enzymes in tears.
Authors: Fiona Stapleton; Carl Marfurt; Blanka Golebiowski; Mark Rosenblatt; David Bereiter; Carolyn Begley; Darlene Dartt; Juana Gallar; Carlos Belmonte; Pedram Hamrah; Mark Willcox Journal: Invest Ophthalmol Vis Sci Date: 2013-10-18 Impact factor: 4.799
Authors: Carlos Belmonte; Jason J Nichols; Stephanie M Cox; James A Brock; Carolyn G Begley; David A Bereiter; Darlene A Dartt; Anat Galor; Pedram Hamrah; Jason J Ivanusic; Deborah S Jacobs; Nancy A McNamara; Mark I Rosenblatt; Fiona Stapleton; James S Wolffsohn Journal: Ocul Surf Date: 2017-07-20 Impact factor: 5.033