Respiratory rhythm generation in a precocial rodent in vitro preparation.

In vitro preparations for studying the neural control of respiration consisting of brainstem and spinal cord regions isolated from the newborn (PO-P1) precocial rodent, Acomys cahirinus (spiny mouse) are described. Spiny mice have a longer gestation period (39 days) than laboratory rats (22 days) and mice (20 days) and thus are born in a considerably more mature state. We sought to determine if in vitro preparations isolated from spiny mice would spontaneously generate a respiratory motor pattern and thus offer a more mature in vitro model than previously established altricial rodent models. Brain stem-spinal cords isolated from newborn spiny mice, unlike comparable Sprague-Dawley preparations, did not generate a sustained respiratory rhythm. However, spiny mice medullary slice preparations consisting of respiratory rhythm centres generated a stable spontaneous respiratory rhythm. Moreover, spiny mice and Sprague-Dawley medullary preparations responded in a similar fashion to excitatory amino acid, glycine, TRH and, mu-opioid receptor agonists and antagonists. Thus, considering the extended period of fetal development and the maturity of the spiny mouse at birth, medullary slice preparations isolated from this precocial rodent will compliment altricial models for the study of developmental and general neuronal mechanisms underlying respiratory control.