K(+) and Ca²(+) dependence of inspiratory-related rhythm in novel "calibrated" mouse brainstem slices.
Recently developed transversal newborn rat brainstem slices with "calibrated" rostrocaudal margins unraveled novel features of rhythmogenic inspiratory active pre-Bötzinger complex (preBötC) neural networks (Ballanyi and Ruangkittisakul, 2009). For example, slice rhythm in physiological (3 mM) superfusate K(+) is depressed by modestly raised Ca²(+) and restored by raised K(+). Correspondingly, we generated here calibrated preBötC slices from commonly used newborn C57BL/6 mice in which rostrocaudal extents of respiratory marker structures, e.g., the inferior olive, turned out to be smaller than in newborn rats. Slices of 400-600 μm thickness with likely centered preBötC kernel ("m-preBötC slices") generated rhythm in 3 mM K(+) and 1mM Ca(2+) for several hours although its rate decreased to < 5 bursts/min after >1 h. Rhythm was stable at 8-12 bursts/min in 6-7 mM K(+), depressed by 2 mM Ca²(+), and restored by 9 mM K(+). Our findings provide the basis for future structure-function analyses of the mouse preBötC, whose activity depends critically on a "Ca(+)/K(+) antagonism" as in rats.
Ruangkittisakul
Araya
A
Department of Physiology & Perinatal Research Centre, Faculty of Medicine & Dentistry, Heritage Medical Research Centre, University of Alberta, Edmonton, Canada.
Panaitescu
Bogdan
B
Ballanyi
Klaus
K
D000200:Action Potentials / Q000502:physiology; D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000166:cytology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002138:Calibration; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D001239:Inhalation / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology; D010507:Periodicity; D058988:Phosphodiesterase 4 Inhibitors / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D020889:Rolipram / Q000494:pharmacology
D058988:Phosphodiesterase 4 Inhibitors; D020889:Rolipram; D011188:Potassium; D002118:Calcium