Acquisition of brains from the African elephant (Loxodonta africana): perfusion-fixation and dissection.

The current correspondence describes the in situ perfusion-fixation of the brain of the African elephant. Due to both the large size of proboscidean brains and the complex behaviour of these species, the acquisition of good quality material for comparative neuroanatomical analysis from these species is important. Three male African elephants (20-30 years) that were to be culled as part of a larger population management strategy were used. The animals were humanely euthanized and the head removed from the body. Large tubes were inserted into to the carotid arteries and the cranial vasculature flushed with a rapid (20 min) rinse of 100 l of cold saline (4 degrees C). Following the rinse the head was perfusion-fixed with a slower rinse (40 min) of 100 l of cold (4 degrees C) 4% paraformaldehyde in 0.1M phosphate buffer. This procedure resulted in well-fixed neural and other tissue. After perfusion the brains were removed from the skull with the aid of power tools, a procedure taking between 2 and 6h. The brains were immediately post-fixed in the same solution for 72 h at 4 degrees C. The brains were subsequently placed in a sucrose solution and finally an antifreeze solution and are stored in a -20 degrees C freezer. The acquisition of high quality neural material from African elephants that can be used for immunohistochemistry and electron microscopy is of importance in understanding the "hardware" underlying the behaviour of this species. This technique can be used on a variety of large mammals to obtain high quality material for comparative neuroanatomical studies.