P2 receptor-stimulation influences axonal outgrowth in the developing hippocampus in vitro

• Published in: Neuroscience 2006, Vol.138 (1), p.303-311
• Main Authors: Heine, C., Heimrich, B., Vogt, J., Wegner, A., Illes, P., Franke, Heike
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - analogs & derivatives; Adenosine Triphosphate - pharmacology; Animals; ATP; Axons - drug effects; Axons - physiology; Biological and medical sciences; Cell Count; Coculture Techniques; Dentate Gyrus - cytology; Dentate Gyrus - drug effects; Entorhinal Cortex - physiology; fiber outgrowth; Fluorescent Antibody Technique, Indirect; Fundamental and applied biological sciences. Psychology; hippocampus; Hippocampus - cytology; Hippocampus - drug effects; Hippocampus - growth & development; Immunohistochemistry; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Nerve Fibers - drug effects; Organ Culture Techniques; organotypic co-cultures; P2 receptor agonist; P2 receptor antagonist; Purinergic P2 Receptor Agonists; Pyridoxal Phosphate - analogs & derivatives; Pyridoxal Phosphate - pharmacology; Stimulation, Chemical; Thionucleotides - pharmacology; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2005.11.056

Extracellular ATP might act as a trophic factor on growing axons during development of the CNS via P2 receptors. In the present study the postnatal presence of selected P2 receptor subtypes was analyzed and their putative trophic capacity in entorhino-hippocampal slice co-cultures of mouse brain was tested. The effect of the P2 receptor ligands 2-methylthioadenosine-5′-triphosphate (P2X/Y receptor agonist) and pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid (P2X/Y receptor antagonist) on axonal growth and fiber density of biocytin-labeled hippocampal projections was compared both with untreated cultures and with cultures treated with artificial cerebrospinal fluid. After 10 days in vitro, double immunofluorescence labeling revealed the expression of P2X 1, P2X 2, P2X 4 as well as P2Y 1 and P2Y 2 receptors in the examined regions of entorhinal fiber termination. Further, quantitative analysis of identified biocytin-traced entorhinal fibers showed a significant increase in fiber density in the dentate gyrus after incubation of the slices with the P2 receptor agonist 2-methylthioadenosine-5′-triphosphate. This neurite outgrowth promoting effect was completely abolished by the P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid. Our in vitro data indicate that ATP via its P2X and P2Y receptors can shape hippocampal connectivity during development.