title: PACAP-mediated neuroprotection of neurochemically identified cell types in MSG-induced retinal degeneration.
abstract: Pituitary adenylate cyclase-activating polypeptide (PACAP) is neuroprotective in animal models of different brain pathologies and injuries, including cerebral ischemia, Parkinson's disease, and different types of retinal degenerations. We have previously shown that PACAP is protective against monosodium glutamate (MSG)-induced retinal degeneration, where PACAP-treated retinas has more retained structure and PACAP induces anti-apoptotic while it inhibits pro-apoptotic signaling pathways. The aim of the present study was to investigate cell-type specific effects of PACAP in MSG-induced retinal degeneration by means of immunohistochemistry. Rat pups received MSG (2 mg/g b.w.) applied on postnatal days 1, 5, and 9. PACAP (100 pmol in 5 microl saline) was injected into the right vitreous body, while the left eye received only saline. Retinas were processed for immunocytochemistry after 3 weeks. Immunolabeling was determined for vesicular glutamate transporter 1, tyrosine hydroxylase, calretinin, calbindin, parvalbumin, and vesicular gamma-aminobutyric acid (GABA) transporter. In the MSG-treated retinas, the cell bodies and processes in the inner nuclear, inner plexiform, and ganglion cell layers displayed less immunoreactivity for all antisera. Apart from photoreceptors, only one major retinal cell type examined in this study; the calbindin-immunoreactive horizontal cell seemed not to be affected by MSG application. After simultaneous application of MSG and PACAP, staining of retinas was similar to that of normal eyes, with no significant alterations in immunoreactive patterns. These findings further support the neuroprotective function of PACAP in MSG-induced retinal degeneration.
authors.affiliation: Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary.
authors.forename: Tamas
authors.initials: T
authors.lastname: Atlasz
authors.forename: Krisztina
authors.initials: K
authors.lastname: Szabadfi
authors.forename: Peter
authors.initials: P
authors.lastname: Kiss
authors.forename: Norbert
authors.initials: N
authors.lastname: Babai
authors.forename: Zsombor
authors.initials: Z
authors.lastname: Koszegi
authors.forename: Andrea
authors.initials: A
authors.lastname: Tamas
authors.forename: Dora
authors.initials: D
authors.lastname: Reglodi
authors.forename: Robert
authors.initials: R
authors.lastname: Gabriel
mesh_terms: D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D005503:Food Additives / Q000494:pharmacology; D007150:Immunohistochemistry; D018696:Neuroprotective Agents / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D012162:Retinal Degeneration / Q000139:chemically induced / Q000473:pathology; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D012970:Sodium Glutamate / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D064026:Calbindins; D005503:Food Additives; D018696:Neuroprotective Agents; D010320:Parvalbumins; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D064030:S100 Calcium Binding Protein G; C493466:Slc17a7 protein, rat; C118623:Slc32a1 protein, rat; D050598:Vesicular Glutamate Transport Protein 1; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; D014446:Tyrosine 3-Monooxygenase; D012970:Sodium Glutamate