title: Putative pacemakers in the eyestalk and brain of the crayfish Procambarus clarkii show circadian oscillations in levels of mRNA for crustacean hyperglycemic hormone.
abstract: Crustacean hyperglycemic hormone (CHH) synthesizing cells in the optic lobe, one of the pacemakers of the circadian system, have been shown to be present in crayfish. However, the presence of CHH in the central brain, another putative pacemaker of the multi-oscillatory circadian system, of this decapod and its circadian transcription in the optic lobe and brain have yet to be explored. Therefore, using qualitative and quantitative PCR, we isolated and cloned a CHH mRNA fragment from two putative pacemakers of the multi-oscillatory circadian system of Procambarus clarkii, the optic lobe and the central brain. This CHH transcript synchronized to daily light-dark cycles and oscillated under dark, constant conditions demonstrating statistically significant daily and circadian rhythms in both structures. Furthermore, to investigate the presence of the peptide in the central brain of this decapod, we used immunohistochemical methods. Confocal microscopy revealed the presence of CHH-IR in fibers and cells of the protocerebral and tritocerebal clusters and neuropiles, particularly in some neurons located in clusters 6, 14, 15 and 17. The presence of CHH positive neurons in structures of P. clarkii where clock proteins have been reported suggests a relationship between the circadian clockwork and CHH. This work provides new insights into the circadian regulation of CHH, a pleiotropic hormone that regulates many physiological processes such as glucose metabolism and osmoregulatory responses to stress.
authors.affiliation: Laboratorio de Neurofisiología Comparada, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Distrito Federal, México.
authors.forename: Janikua
authors.initials: J
authors.lastname: Nelson-Mora
authors.affiliation: Laboratorio de Neurofisiología Comparada, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Distrito Federal, México.
authors.forename: Julio
authors.initials: J
authors.lastname: Prieto-Sagredo
authors.affiliation: Laboratorio de Neurofisiología Comparada, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Distrito Federal, México.
authors.forename: Rosaura
authors.initials: R
authors.lastname: Loredo-Ranjel
authors.affiliation: Laboratorio de Neurofisiología Comparada, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Distrito Federal, México.
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Fanjul-Moles
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics* / Q000378:metabolism; D003400:Astacoidea / Q000166:cytology / Q000378:metabolism*; D001683:Biological Clocks / Q000502:physiology*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D005123:Eye / Q000166:cytology / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007447:Invertebrate Hormones / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C015947:hyperglycemic hormone, crustacean