RESUMEN
The presence of the pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors PAC(1), VPAC(1), and VPAC(2) was studied in the lizard Podarcis sicula gastrointestinal and respiratory tissues. The expression and distribution of this neuropeptide was investigated using RT-PCR, immunohistochemistry, and in situ hybridization techniques. RT-PCR showed that several tissues of this reptile synthesize an mRNA encoding for PACAP. Performing in situ hybridization and immunohistochemistry, we found a wide distribution of PACAP and its mRNA in intestine, stomach, liver, and lung. PACAP receptors possess a specific distribution in both gastrointestinal and respiratory system. Further, we analyzed the conservation of PACAP amino acid sequence demonstrating that this peptide in the lizard is very similar to that of other vertebrates. Our findings suggest that also in reptiles an effective PACAP system is present and that it could be implicated in some essential physiological functions as a result of its high conservation amongst vertebrates.
Asunto(s)
Evolución Molecular , Lagartos/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , Secuencia de Aminoácidos , Animales , Humanos , Inmunohistoquímica , Hibridación in Situ , Lagartos/anatomía & histología , Lagartos/genética , Datos de Secuencia Molecular , Filogenia , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/clasificación , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/genética , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Distribución TisularRESUMEN
The pituitary adenylate cyclase-activating polypeptide (PACAP) is considered a pleiotropic neuropeptide in vertebrate physiology. The nucleotide sequence, the expression and the distribution of PACAP were determined in the brain of the lizard Podarcis sicula. RT-PCR showed that the brain of this reptile synthesizes an mRNA coding for PACAP. By performing in situ hybridization and immunohistochemistry techniques, a wide distribution of PACAP and its mRNA in neurons, nervous fibers and other cells was found. Phylogenetic sequence analysis indicates that lizard PACAP is highly conserved, resembling the vertebrate PACAP. Our data demonstrate that PACAP is not only highly preserved during vertebrate evolution but also suggest that PACAP could be implicated in a wide number of functions in the physiology of the reptile brain.