Effects of PACAP on the oxidative stress-induced cell death in chicken pinealocytes is influenced by the phase of the circadian clock.
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with highly potent neuro- and general cytoprotective actions. PACAP is also an important modulator of circadian rhythmic functions, including time-dependent effects in the pineal gland. It is not known whether PACAP influences the survival of pinealocytes. The present study had two aims. First, we tested whether the cytoprotective effects of PACAP are present also in the pineal cells. As the pineal gland is the main circadian master clock in birds, we also tested whether this effect depends on the time of day. Using flow cytometry, we detected a significant decrease of cell viability after hydrogen peroxide-induced oxidative stress in chicken pinealocytes. PACAP alone did not influence cell survival. Co-incubation with PACAP in the dark phase (9 PM) was able to attenuate the toxic effect of H2O2. The survival-promoting effect could be counteracted by simultaneously applied PACAP antagonist, PACAP6-38. However, co-treatment with PACAP during the light phase (9 AM) did not result in significant differences in the percentage of living cells. In summary, our results show that PACAP has a protective effect against the oxidative stress-induced cell death in chicken pinealocytes, but this effect is dependent on the phase of the circadian biological clock.
Horvath
Gabriella
G
Department of Anatomy, University of Pecs, Hungary.
Reglodi
Dora
D
Opper
Balazs
B
Brubel
Reka
R
Tamas
Andrea
A
Kiss
Peter
P
Toth
Gabor
G
Csernus
Valer
V
Matkovits
Attila
A
Racz
Boglarka
B
D000818:Animals; D000831:Animals, Newborn; D017304:Annexin A5 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002645:Chickens; D057906:Circadian Clocks / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D010870:Pineal Gland / Q000166:cytology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000494:pharmacology*
D017304:Annexin A5; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D006861:Hydrogen Peroxide