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ISSN 2522-9028 (Print)
ISSN 2522-9036 (Online)
DOI: https://doi.org/10.15407/fz

Fiziologichnyi Zhurnal

is a scientific journal issued by the

Bogomoletz Institute of Physiology
National Academy of Sciences of Ukraine

Editor-in-chief: V.F. Sagach

The journal was founded in 1955 as
1955 – 1977 "Fiziolohichnyi zhurnal" (ISSN 0015 – 3311)
1978 – 1993 "Fiziologicheskii zhurnal" (ISSN 0201 – 8489)
1994 – 2016 "Fiziolohichnyi zhurnal" (ISSN 0201 – 8489)
2017 – "Fiziolohichnyi zhurnal" (ISSN 2522-9028)

Fiziol. Zh. 2009; 55(2): 44-49

Morphophysiologic properties of delayed firing neurons in substantia gelatinosa of the rat spinal cord

I.V. Melnick

    O.O. Bogomoletz Institute of Physiology, National AcademySciences of Ukraine, Kyiv, Ukraine



Abstract

Substantia gelatinosa (SG) neurons of the spinal cord are highly heterogeneous in their morphologic and physiologic properties. Based on characteristic firing response evoked by sustained depolarization, neurons can be categorized on three main types: tonic, adapting and delayed firing (DFNs). Here, properties of DFNs in spinal cord slices from 3-5 weeks-old rats were stud-ied with the use of patch-clamp recording and confocal micros-copy. Distinctive features of DFNs were increased rheobase (95.7 ± 11.2 pA) and depolarized threshold to evoke action potential (-37.8 ± 0.7 mV) than in neurons of other types. In volt-age-clamp mode all DFNs expressed high amplitude outward A-type potassium current (KA which started activation at ~ -70 mV, before Na+ current. Structurally, the majority of DFNs had vertically oriented dendritic tree, while their axons were not restricted to SG and projected predominantly to lamina I. Possible physiological functions of DFNs are discussed.

Keywords: Substantia gelatinosa, spinal cord

Full text: (PDF, in English)

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