Characterization of deep dorsal horn neurones in the rat spinal cord in vitro: synaptic and excitatory amino acid induced excitations.
1. Two in vitro spinal cord preparations obtained from young rats (10-16 days), the transverse slice and the hemisected cord, have been utilized to examine the properties of deep dorsal horn neurones. 2. Several features have emerged: neurones respond to direct current injection with repetitive firing which is characteristically tonic in nature with little adaptation. Over the current intensities tested, no secondary firing range was apparent. 3. Graded afferent fibre stimulation produces a variety of sub- and suprathreshold postsynaptic excitatory potentials. The latencies of these potentials range from tens of milliseconds to hundreds of milliseconds, with the former predominating. 4. The majority of neurones are strongly excited by all three agonists: glutamate, quisqualate and N-methyl-D-aspartate but in addition a subpopulation of neurones with low sensitivity to glutamate and N-methyl-D-aspartate exists. 5. The implications of such properties for sensory processing within the dorsal horn are discussed.
King
A E
AE
Department of Anatomy and Developmental Biology, University College London, UK.
Thompson
S W
SW
D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004558:Electric Stimulation; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D016202:N-Methylaspartate; D009474:Neurons / Q000502:physiology*; D010069:Oxadiazoles / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology*
D005971:Glutamates; D010069:Oxadiazoles; D001224:Aspartic Acid; D018698:Glutamic Acid; D016202:N-Methylaspartate; D016318:Quisqualic Acid