PACAP inhibits anoxia-induced changes in physiological responses in horizontal cells in the turtle retina.
Pituitary adenylate cyclase activating polypeptide (PACAP) has neurotrophic and neuroprotective effects against various cytotoxic agents in vitro, and ischemia in vivo. Anoxia tolerance is most highly developed in some species of turtles. Recently, we have demonstrated high levels of PACAP38 in the turtle brain, exceeding those in corresponding rat and human brain areas by 10- to 100-fold. The aim of the present study was to investigate with electrophysiological methods the protective effects of PACAP in anoxia-induced neuronal damage of turtle retinal horizontal cells. Adult turtles (Pseudemys scripta elegans) were used for the experiments. After decapitation, half of the isolated eyecup slices were placed into a non-oxygenated Ringer solution, the other half into 0.165 microM PACAP solution. Intracellular recordings were obtained from horizontal cells 18, 22, 42 and 46 h after removal of the eyes. The amplitudes of light responses with the exception of the 0-h measurement, were larger at all time-points in PACAP-incubated slices than in control retinal slices. After both 18 and 22 h, the response amplitudes of PACAP-treated cells exceeded those taken from control horizontal cells by 1.2-fold. At later times, this difference became larger than 2-fold. In summary, the present results provide evidence that PACAP has neuroprotective effects on the anoxic retinal cells in the turtle.
Rábl
Katalin
K
Department of General Zoology and Neurobiology, University of Pécs, Pécs, Hungary.
Reglodi
Dóra
D
Bánvölgyi
Tamás
T
Somogyvári-Vigh
Anikó
A
Lengvári
István
I
Gábriel
Róbert
R
Arimura
Akira
A
D000818:Animals; D000860:Hypoxia / Q000473:pathology / Q000503:physiopathology*; D066298:In Vitro Techniques; D008027:Light; D009479:Neuropeptides / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012160:Retina / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology* / Q000528:radiation effects; D013997:Time Factors; D014426:Turtles / Q000502:physiology
D009479:Neuropeptides; D018696:Neuroprotective Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide