MEMBRANE-PROPERTIES OF DEEP DORSAL HORN NEURONS FROM NEONATAL RAT SPINAL-CORD IN-VITRO

Whole-cell patch-clamp recordings were undertaken to characterize and compare the membrane properties of deep dorsal horn neurons in transve rse slices of rat lumbar spinal cord in two age groups, postnatal days (P) 3-6 and 9-16. In both age groups, significant correlations were o bserved between membrane time constant and cell resistance and between action potential height and its duration at half-maximal amplitude. C ell resistance and action potential half-width values were lower in th e P9-16 age group. Neurons were divided into four categories based on their firing properties in response to intracellular current injection : single spike, phasic firing, repetitive firing, and delayed firing. The distribution of neurons within these categories was similar in bot h age groups which suggests that the firing properties of deep dorsal horn neurons rue functionally differentiated at an early postnatal age . (C) 1997 Elsevier Science B.V.