title: Structural and Morphometric Comparison of Lower Incisors in PACAP-Deficient and Wild-Type Mice.
abstract: Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with widespread distribution. PACAP plays an important role in the development of the nervous system, it has a trophic and protective effect, and it is also implicated in the regulation of various physiological functions. Teeth are originated from the mesenchyme of the neural crest and the ectoderm of the first branchial arch, suggesting similarities with the development of the nervous system. Earlier PACAP-immunoreactive fibers have been found in the odontoblastic and subodontoblastic layers of the dental pulp. Our previous examinations have shown that PACAP deficiency causes alterations in the morphology and structure of the developing molars of 7-day-old mice. In our present study, morphometric and structural comparison was performed on the incisors of 1-year-old wild-type and PACAP-deficient mice. Hard tissue density measurements and morphometric comparison were carried out on the mandibles and the lower incisors with micro-CT. For structural examination, Raman microscopy was applied on frontal thin sections of the mandible. With micro-CT morphometrical measurements, the size of the incisors and the relative volume of the pulp to dentin were significantly smaller in the PACAP-deficient group compared to the wild-type animals. The density of calcium hydroxyapatite in the dentin was reduced in the PACAP-deficient mice. No structural differences could be observed in the enamel with Raman microscopy. Significant differences were found in the dentin of PACAP-deficient mice with Raman microscopy, where increased carbonate/phosphate ratio indicates higher intracrystalline disordering. The evaluation of amide III bands in the dentin revealed higher structural diversity in wild-type mice. Based upon our present and previous results, it is obvious that PACAP plays an important role in tooth development with the regulation of morphogenesis, dentin, and enamel mineralization. Further studies are required to clarify the molecular background of the effects of PACAP on tooth development.
authors.affiliation: Department of Dentistry, Oral and Maxillofacial Surgery, Pecs, Hungary.|Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, Szigeti 12, Pecs, 7624, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Sandor
authors.affiliation: Department of Mineralogy, Geochemistry and Petrology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
authors.forename: K
authors.initials: K
authors.lastname: Fintor
authors.affiliation: Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, Szigeti 12, Pecs, 7624, Hungary.
authors.forename: D
authors.initials: D
authors.lastname: Reglodi
authors.affiliation: Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, Szigeti 12, Pecs, 7624, Hungary.
authors.forename: D B
authors.initials: DB
authors.lastname: Fulop
authors.affiliation: Department of Pharmacology and Pharmacotherapy, Medical School, Szentagothai Research Center, University of Pecs, Pecs, Hungary.|MTA-NAP B Chronic Pain Research Group, Pecs, Hungary.
authors.forename: Z
authors.initials: Z
authors.lastname: Helyes
authors.affiliation: Department of Dentistry, Oral and Maxillofacial Surgery, Pecs, Hungary.
authors.forename: I
authors.initials: I
authors.lastname: Szanto
authors.affiliation: Department of Pharmacology and Pharmacotherapy, Medical School, Szentagothai Research Center, University of Pecs, Pecs, Hungary.
authors.forename: P
authors.initials: P
authors.lastname: Nagy
authors.affiliation: School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, Szigeti 12, Pecs, 7624, Hungary. andreatamassz@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Tamas
mesh_terms: D000818:Animals; D002254:Carbonates / Q000032:analysis; D003743:Dental Enamel / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D017886:Durapatite / Q000032:analysis; D007180:Incisor / Q000737:chemistry / Q000254:growth & development / Q000648:ultrastructure*; D008297:Male; D051379:Mice; D010710:Phosphates / Q000032:analysis; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000172:deficiency / Q000235:genetics*
chemical_list: D002254:Carbonates; D010710:Phosphates; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D017886:Durapatite
keywords: Development; Micro-CT; PACAP; Raman; Tooth