Atlas of the fore- and midbrain of the brown antechinus (Antechinus stuartii)

Introduction

The brain of this small dasyurid marsupial (brown antechinus - Antechinus stuartii) is of particular scientific interest because of its value as a model of the effects of stress on central nervous system structure and function.  Brown antechinus have a precisely synchronised life history and males have only a single breeding opportunity.  During late winter and early spring, males engage in a short mating period, characterised by highly aggressive territorial behaviour.  This brief mating period is followed by universal male death, or male semelparity (Tyndale-Biscoe, 2005; Naylor et al., 2008), due to failure of glucocorticoid feedback, immune system collapse and overwhelming parasitic infestations.  By contrast, females often live to reproduce a second year (McAllan, 2003, Naylor et al., 2008).  This life cycle has been termed “big bang reproduction” by some authors (Tyndale-Biscoe, 2005).  

Materials and Methods

All procedures conformed to the guidelines of the Australian National Health and Medical Research Council and were approved by the University of NSW Animal Care and Ethics Committee.  Brown antechinus were captured live in the Blue Mountains west of Sydney under licence from the NSW National Parks and Wildlife Service.  Animals were deeply anaesthetised with pentobarbitone sodium (60 mg/kg body weight), delivered by intraperitoneal injection, prior to transcardial perfusion with Zamboni’s fixative. The brains were embedded in paraffin, sectioned coronally at a thickness of 14 µm and stained with cresyl violet or processed for immunohistochemistry.   Photomicrographs were taken with an Olympus BX51 Tiling microscope.  Images were processed using Adobe Photoshop CS2 and photomicrographs of some sections were digitally enhanced to maximise contrast.  Photomicrographs were placed in Adobe Illustrator CS2 for labelling.  

References

McAllan BM (2003) Timing of reproduction in carnivorous marsupials. In: Predators with pouches: The biology of carnivorous marsupials. Jones M, Dickman C, Archer M eds. Chapter 10, pt 2, pp 147-164. Sydney: CSIRO.

 Naylor R, Richardson SJ, McAllan BM (2008) Boom and bust: a review of the physiology of the marsupial genus Antechinus. Journal of Comparative Physiology B 178, 545-62.

Tyndale-Biscoe H (2005) Life of Marsupials. Collingwood: CSIRO.

List of Abbreviations