title: The developing left superior cervical ganglion of Pacas (Agouti paca).
abstract: In this study the main question investigated was the number and size of both binucleate and mononucleate superior cervical ganglion (SCG) neurons and, whether post-natal development would affect these parameters. Twenty left SCGs from 20 male pacas were used. Four different ages were investigated, that is newborn (4 days), young (45 days), adult (2 years), and aged animals (7 years). By using design-based stereological methods, that is the Cavalieri principle and a physical disector combined with serial sectioning, the total volume of ganglion and total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal (somal) volume of mononucleate and binucleate neurons was estimated using the vertical nucleator. The main findings of this study were a 154% increase in the SCG volume, a 95% increase in the total number of mononucleate SCG neurons and a 50% increase in the total volume of SCG neurons. In conclusion, apart from neuron number, different adaptive mechanisms may coexist in the autonomic nervous system to guarantee a functional homeostasis during ageing, which is not always associated with neuron losses.
authors.affiliation: Laboratory of Stochastic Stereology and Chemical Anatomy, Department of Surgery, College of Veterinary Medicine, University of São Paulo (USP), São Paulo, Brazil.
authors.forename: Samanta Rios
authors.initials: SR
authors.lastname: Melo
authors.forename: Jens Randel
authors.initials: JR
authors.lastname: Nyengaard
authors.forename: Felipe
authors.initials: F
authors.lastname: da Roza Oliveira
authors.forename: Fernando Vagner Lobo
authors.initials: FV
authors.lastname: Ladd
authors.forename: Luciana Maria Bigaram
authors.initials: LM
authors.lastname: Abrahão
authors.forename: Márcia R F
authors.initials: MR
authors.lastname: Machado
authors.forename: Tais H C
authors.initials: TH
authors.lastname: Sasahara
authors.forename: Mariana Pereira
authors.initials: MP
authors.lastname: de Melo
authors.forename: Antonio Augusto C M
authors.initials: AA
authors.lastname: Ribeiro
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D017776:Autonomic Pathways / Q000166:cytology / Q000254:growth & development; D002320:Cardiovascular Physiological Phenomena; D002452:Cell Count; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D049109:Cell Proliferation; D048429:Cell Size; D007839:Functional Laterality / Q000502:physiology; D008297:Male; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology*; D012377:Rodentia / Q000033:anatomy & histology* / Q000254:growth & development*; D013045:Species Specificity; D017783:Superior Cervical Ganglion / Q000166:cytology* / Q000254:growth & development*; D017779:Sympathetic Fibers, Postganglionic / Q000166:cytology / Q000254:growth & development