Pituitary adenylate cyclase-activating polypeptide (PACAP) can act as determinant of the tyrosine hydroxylase phenotype of dopaminergic cells during retina development.
In the chick retina, dopaminergic cells are generated between embryonic days 3 and 7 (E3/E7). However, the expression of tyrosine hydroxylase (TH), the first enzyme in the catecholamine synthetic pathway, is only detected after E11/E12. During the interval comprising E7 to E12, signals conveyed by cAMP are important to determine the TH phenotype. The present study shows that pituitary adenylyl cyclase-activating polypeptide (PACAP), via cAMP, is a major endogenous component in defining the TH phenotype of retina dopaminergic cells during development. PACAP type 1 receptor and its mRNA were detected in retinas since E6. PACAP was also immunodetected in cells localized in the inner nuclear layer of retinas since E8. This peptide promoted greater than 10-fold increase in cAMP accumulation of retinas obtained from embryos since E8, an effect that was blocked by PACAP6-38 (PAC1 receptor antagonist). In cultured retina cells from E8 and E9, maintained for 6 days in vitro with 10 nM PACAP (for 5 days), the number of dopaminergic cells expressing tyrosine hydroxylase increased 2.4-fold. The cAMP analog, 8-Br-cAMP and 3-isobutyl-1-methylxanthine (IBMX, a phosphodiesterase inhibitor) also increased the number of tyrosine hydroxylase-positive cells by 4- to 6-fold. IBMX plus PACAP treatment resulted in 17-fold increase in the number of cells positive for tyrosine hydroxylase. Under this condition the amount of tyrosine hydroxylase expression, as detected by western blot analysis, was also increased. The protein kinase-A inhibitor, rp-cAMPS, significantly reduced the effect of PACAP. Our data show that this peptide is an important factor influencing the definition of the tyrosine hydroxylase phenotype of retina dopaminergic cells within a narrow window of development.
Borba
Juliana Carrazzoni
JC
Laboratórios de Neuroquímica and Neurobiologia da Retina, Instituto de Biofísica Carlos Chagas Filho-UFRJ, Centro de Ciências da Saúde-Bloco G, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ 21949-900, Brazil.
Henze
Isabela Pereira
IP
Silveira
Mariana Souza
MS
Kubrusly
Regina Célia Cussa
RC
Gardino
Patrícia Franca
PF
de Mello
Maria Christina Fialho
MC
Hokoç
Jan Nora
JN
de Mello
Fernando Garcia
FG
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D002452:Cell Count / Q000379:methods; D018929:Cell Culture Techniques; D002642:Chick Embryo; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D009414:Nerve Growth Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000037:antagonists & inhibitors / Q000502:physiology*; D010641:Phenotype; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000201:enzymology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*
D009414:Nerve Growth Factors; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D010726:Phosphodiesterase Inhibitors; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000242:Cyclic AMP; D014446:Tyrosine 3-Monooxygenase; D015056:1-Methyl-3-isobutylxanthine; D004298:Dopamine