PURPOSE: To verify at the molecular level that P2 receptors are expressed in the lens and to determine their expression profiles. METHODS: The reverse transcription-polymerase chain reaction (RT-PCR) was used to screen rat lens epithelial and fiber cells for the expression of the ionotropic P2X2 receptor and the G-protein-linked receptor isoforms P2Y1 and P2Y2. Northern blot analysis was used to confirm the level of expression of P2Y1 and P2Y2. The profile of P2-receptor isoform expression in the lens was identified using an indirect RT-PCR in situ hybridization procedure on paraffin sections of whole rat eyes. RESULTS: P2X2-receptor transcripts could not be detected in lens epithelial or fiber cells. P2Y1- and P2Y2-receptor transcripts were detected in lens fiber cells but not in the epithelial cells. Their expression profiles were maximal in the lens cortex and mostly overlapped each other, except that transcripts for the P2Y2-receptor isoform appeared earlier in the not yet fully elongated fiber cells in the lens bow region. CONCLUSIONS: The molecular data support physiological evidence previously reported by others that P2Y receptors are expressed in the lens and identifies cortical fiber cells as the principal site of expression.
PURPOSE: To verify at the molecular level that P2 receptors are expressed in the lens and to determine their expression profiles. METHODS: The reverse transcription-polymerase chain reaction (RT-PCR) was used to screen rat lens epithelial and fiber cells for the expression of the ionotropic P2X2 receptor and the G-protein-linked receptor isoforms P2Y1 and P2Y2. Northern blot analysis was used to confirm the level of expression of P2Y1 and P2Y2. The profile of P2-receptor isoform expression in the lens was identified using an indirect RT-PCR in situ hybridization procedure on paraffin sections of whole rat eyes. RESULTS: P2X2-receptor transcripts could not be detected in lens epithelial or fiber cells. P2Y1- and P2Y2-receptor transcripts were detected in lens fiber cells but not in the epithelial cells. Their expression profiles were maximal in the lens cortex and mostly overlapped each other, except that transcripts for the P2Y2-receptor isoform appeared earlier in the not yet fully elongated fiber cells in the lens bow region. CONCLUSIONS: The molecular data support physiological evidence previously reported by others that P2Y receptors are expressed in the lens and identifies cortical fiber cells as the principal site of expression.