Selective vulnerability to ischemia in the rat spinal cord: a comparison between ventral and dorsal horn neurons.
METHODS
Whole-cell patch-clamp recordings were performed from ventral horn (VH) and dorsal horn (DH) neurons obtained from the rat spinal cord slices.


OBJECTIVE
This study investigated which is more vulnerable to ischemia, spinal VH neurons or DH neurons.


BACKGROUND
Spinal cord ischemia or injury sometimes causes a greater loss of motor function than of sensory function in patients. However, it is difficult to evaluate whether spinal motor neurons are more vulnerable than sensory neurons because of the anatomic complexity and a variety of physiologic factors in the spinal cord.


METHODS
Whole-cell patch-clamp recordings were performed from VH and DH neurons obtained from the spinal cord slices. Ischemia was simulated by superfusing an oxygen- and glucose-deprived medium (ischemia simulating medium [ISM]).


RESULTS
Perfusion with ISM generated an agonal depolarization in all VH and DH neurons recorded in current-clamp mode. Following ISM superfusion, an agonal inward current was produced at a holding potential of -70 mV in all VH and DH neurons tested in voltage-clamp mode. The agonal inward current consisted of a slow and subsequent rapid inward current. The average latency of the rapid inward currents after ISM exposures in VH neurons was significantly shorter than that in DH neurons. The average amplitude of the agonal inward currents in VH neurons was significantly bigger than that of DH neurons. Moreover, the recovery ratio by the reintroduction of oxygen and glucose in VH neurons was smaller than that in DH neurons.


CONCLUSIONS
These results suggest that VH neurons are more vulnerable to ischemia than DH neurons. This finding may help in achieving a better understanding of the difference between motor and sensory disturbance in spinal cord ischemia or injury patients.
Nohda
Kazuhiro
K
Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, Japan.
Nakatsuka
Terumasa
T
Takeda
Daisuke
D
Miyazaki
Nobuyuki
N
Nishi
Hideto
H
Sonobe
Hideki
H
Yoshida
Munehito
M
D000818:Animals; D000870:Anterior Horn Cells / Q000502:physiology*; D003470:Culture Media / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000494:pharmacology; D007511:Ischemia / Q000503:physiopathology*; D009924:Organ Culture Techniques; D010100:Oxygen / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D020671:Posterior Horn Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003470:Culture Media; D005947:Glucose; D010100:Oxygen