TY - JOUR
T1 - Intrinsic properties of mouse lumbar motoneurons revealed by intracellular recording in vivo
AU - Meehan, Claire Francesca
AU - Sukiasyan, Natalya
AU - Zhang, Mengliang
AU - Nielsen, Jens Bo
AU - Hultborn, Hans
N1 - CURIS 2010 5200 089
PY - 2010/5
Y1 - 2010/5
N2 - We have developed an in vivo model for intracellular recording in the adult anesthetized mouse using sharp microelectrode electrodes as a basis for investigations of motoneuron properties in transgenic mouse strains. We demonstrate that it is possible to record postsynaptic potentials underlying identified circuits in the spinal cord. Forty-one motoneurons with antidromic spike potentials (>50 mV) from the sciatic nerve were investigated. We recorded the intrinsic properties of the neurons, including input resistance (mean: 2.4 ± 1.2 MΩ), rheobase (mean: 7.1 ± 5.9 nA), and the duration of the afterhyperpolarization (AHP; mean: 55.3 ± 14 ms). We also measured the minimum firing frequencies (Fmin, mean 23.5 ± 5.7 SD Hz), the maximum firing frequencies (Fmax; >300 Hz) and the slope of the current-frequency relationship ( f-I slope) with increasing amounts of current injected (mean: 13±5.7 Hz/nA). Signs of activation of persistent inward currents (PICs) were seen, such as accelerations of firing frequency or jumps in the membrane potential with increasing amounts of injected current. It is likely that the particular anesthetic regime with a mixture of Hypnorm and midazolam is essential for the possibility to evoke PICs. The data demonstrate that mouse spinal motoneurons share many of the same properties that have been demonstrated previously for cat, rat, and human motoneurons. The shorter AHP duration, steeper f-I slopes, and higher F min and Fmax than those in rats, cats, and humans are likely to be tailored to the characteristics of the mouse muscle contraction properties.
AB - We have developed an in vivo model for intracellular recording in the adult anesthetized mouse using sharp microelectrode electrodes as a basis for investigations of motoneuron properties in transgenic mouse strains. We demonstrate that it is possible to record postsynaptic potentials underlying identified circuits in the spinal cord. Forty-one motoneurons with antidromic spike potentials (>50 mV) from the sciatic nerve were investigated. We recorded the intrinsic properties of the neurons, including input resistance (mean: 2.4 ± 1.2 MΩ), rheobase (mean: 7.1 ± 5.9 nA), and the duration of the afterhyperpolarization (AHP; mean: 55.3 ± 14 ms). We also measured the minimum firing frequencies (Fmin, mean 23.5 ± 5.7 SD Hz), the maximum firing frequencies (Fmax; >300 Hz) and the slope of the current-frequency relationship ( f-I slope) with increasing amounts of current injected (mean: 13±5.7 Hz/nA). Signs of activation of persistent inward currents (PICs) were seen, such as accelerations of firing frequency or jumps in the membrane potential with increasing amounts of injected current. It is likely that the particular anesthetic regime with a mixture of Hypnorm and midazolam is essential for the possibility to evoke PICs. The data demonstrate that mouse spinal motoneurons share many of the same properties that have been demonstrated previously for cat, rat, and human motoneurons. The shorter AHP duration, steeper f-I slopes, and higher F min and Fmax than those in rats, cats, and humans are likely to be tailored to the characteristics of the mouse muscle contraction properties.
U2 - 10.1152/jn.00668.2009
DO - 10.1152/jn.00668.2009
M3 - Journal article
C2 - 20164401
SN - 0022-3077
VL - 103
SP - 2599
EP - 2610
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
IS - 5
ER -