Long-term potentiation and long-term depression of primary afferent neurotransmission in the rat spinal cord

• Published in: The Journal of neuroscience 1993-12, Vol.13 (12), p.5228-5241
• Main Authors: Randic, M, Jiang, MC, Cerne, R
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Capsaicin - pharmacology; Central nervous system; Electrophysiology; Female; Fundamental and applied biological sciences. Psychology; GABA Antagonists; Long-Term Potentiation - drug effects; Long-Term Potentiation - physiology; Male; N-Methylaspartate - physiology; Neurons, Afferent - physiology; Quinoxalines - pharmacology; Rats; Spinal Cord - physiology; Synapses - drug effects; Synapses - physiology; Synaptic Transmission - drug effects; Synaptic Transmission - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/jneurosci.13-12-05228.1993

Synaptic transmission between dorsal root afferents and neurons in the superficial laminae of the spinal dorsal horn (laminae I-III) was examined by intracellular recording in a transverse slice preparation of rat spinal cord. Brief high-frequency electrical stimulation (300 pulses at 100 Hz) of primary afferent fibers produced a long-term potentiation (LTP) or a long-term depression (LTD) of fast (monosynaptic and polysynaptic) EPSPs in a high proportion of dorsal horn neurons. Both the AMPA and the NMDA receptor-mediated components of synaptic transmission at the primary afferent synapses with neurons in the dorsal horn can exhibit LTP and LTD of the synaptic responses. In normal and neonatally capsaicin-treated rats, the induction of LTP requires the activation of NMDA receptor-gated conductances. The induction of LTP or LTD, however, was not abolished in the presence of bicuculline, a GABAA receptor antagonist. The results demonstrate that distinct and long-lasting modulation in synaptic efficiency can be induced at primary afferent synapses with neurons in the superficial laminae of spinal dorsal horn by high-frequency stimulation of dorsal root afferents and that these changes may be physiologically relevant for transmission and integration of sensory information, including pain.