Anatomical and Electrophysiological Comparison of CA1 Pyramidal Neurons of the Rat and Mouse

• Published in: Journal of neurophysiology 2009-10, Vol.102 (4), p.2288-2302
• Main Authors: Routh, Brandy N, Johnston, Daniel, Harris, Kristen, Chitwood, Raymond A
• Format: Article
• Language: English
• Subjects: Animals; CA1 Region, Hippocampal - cytology; CA1 Region, Hippocampal - physiology; Computer Simulation; Dendrites - physiology; Dendritic Spines - physiology; Electric Impedance; In Vitro Techniques; Kinetics; Male; Membrane Potentials - physiology; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Models, Neurological; Neurons - cytology; Neurons - physiology; Patch-Clamp Techniques; Pyramidal Cells - cytology; Pyramidal Cells - physiology; Rats; Rats, Sprague-Dawley; Species Specificity
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00082.2009

Center for Learning and Memory, University of Texas at Austin, Austin, Texas Submitted 29 January 2009; accepted in final form 7 August 2009 ABSTRACT The study of learning and memory at the single-neuron level has relied on the use of many animal models, most notably rodents. Although many physiological and anatomical studies have been carried out in rats, the advent of genetically engineered mice has necessitated the comparison of new results in mice to established results from rats. Here we compare fundamental physiological and morphological properties and create three-dimensional compartmental models of identified hippocampal CA1 pyramidal neurons of one strain of rat, Sprague–Dawley, and two strains of mice, C57BL/6 and 129/SvEv. We report several differences in neuronal physiology and anatomy among the three animal groups, the most notable being that neurons of the 129/SvEv mice, but not the C57BL/6 mice, have higher input resistance, lower dendritic surface area, and smaller spines than those of rats. A surprising species-specific difference in membrane resonance indicates that both mouse strains have lower levels of the hyperpolarization-activated nonspecific cation current I h . Simulations suggest that differences in I h kinetics rather than maximal conductance account for the lower resonance. Our findings indicate that comparisons of data obtained across strains or species will need to account for these and potentially other physiological and anatomical differences. Address for reprint requests and other correspondence: R. A. Chitwood, Center for Learning and Memory, University of Texas at Austin, 1 University Station, C7000, Austin, TX 78712 (E-mail: randy{at}mail.clm.utexas.edu ).