Expression of purinergic receptors (P2X, P2Y) in developing mammalian retina

Abstract

Abstract: : Purpose: Purinergic neurotransmission has recently been shown to play an important role in early retinal development, including the formation of early stage retinal waves. To understand which types of purinergic receptors may be involved in the generation of early retinal activity, we used immunohistochemical methods to localize ionotropic P2X (P2X₁, P2X₂, P2X₃, P2X₄, P2X₆, P2X₇) and metabotropic P2Y (P2Y₁, P2Y₂, P2Y₄, P2Y₆, P2Y₁₂) receptors in the radial sections of the retina. Methods: Eyes from late embryonic and early postnatal mice were fixed with 4% paraformaldehyde and sectioned at a thickness of 10 µm on a –20°C cryostat, and stored at –80°C until staining. Polyclonal antibodies for the above–mentioned P2X and P2Y receptors (procured commercially) were stained using standard immunohistochemical methods. Results: Immunohistochemical labeling for P2X₇, P2Y₁, and P2Y₂ was expressed in the inner layers of the mouse retina at embryonic day 17, which continued into postnatal day 30. Expressions of these receptors were clearly seen in inner plexiform layer and ganglion cell layer. Faint expression of P2X₄ in these layers was observed as well. However, no immunoreactivity to other P2X or P2Y receptors was detected in the retina. Conclusions: These data suggest that the regulation of early retinal activity by ATP may occur through both ionotropic and metabotropic purinergic receptors.

Keywords: retinal development • immunohistochemistry • microscopy: light/fluorescence/immunohistochemistry