Biomaterial Database

Excitatory amino acid receptor-mediated neurotransmission from cutaneous afferents in rat dorsal horn in vitro. 1993

A E King, and J A Lopez-Garcia

Department of Physiology, University of Leeds.

1. The cutaneous mechanoreceptive fields (RFs) of forty-two lumbar dorsal horn neurones have been examined intracellularly using the hemisected spinal cord-hindlimb preparation of 10 to 14-day-old rats. The neurones were classified into three groups on the basis of their excitatory responses to innocuous and noxious mechanical stimulation; the majority (25/42) were activated by noxious and innocuous stimuli and were classed as 'wide-dynamic' type (WDR). 'Nociceptive-specific' neurones (NS) which were excited by noxious stimuli made up the next largest group (12/42) followed by 'low-threshold' neurones (LT, 5/42) which responded only weakly to noxious stimuli. Another fourteen neurones which did not respond to peripheral stimuli were used to test antagonist selectivity against excitatory amino acid agonists. 2. The response to light touch or pinch consisted of an initial EPSP and cell firing followed by subthreshold EPSPs. The mean +/- S.E.M. values for the amplitude (mV) and the duration (s) of the EPSP produced by noxious pinch were significantly greater than those to touch; in WDR neurones the respective values were 14.3 +/- 0.9 vs. 11.5 +/- 0.7 mV (P < 0.01) and 11.9 +/- 1.8 vs. 4.8 +/- 0.6 s (P < 0.01). 3. The non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 3-5 microM) antagonized DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA)-induced depolarizations. The amplitude and duration of the EPSPs produced in response to low- and high-threshold mechanical stimulation were potently attenuated and cell firing was abolished in WDR, NS, LT neurones. A similar profile of antagonism was produced in five WDR neurones superfused with ACSF containing 1 mM D-serine. 4. The NMDA-receptor antagonist D-aminophosphonovalerate (D-AP5, 50 microM) attenuated the EPSP amplitude and duration but never abolished cell firing produced by low- and high-intensity cutaneous mechanical stimulation. A preferential effect of D-AP5 against the EPSP duration resulted in failure of longer latency spikes. 5. The data indicate that non-NMDA receptors contribute substantially to dorsal horn neurotransmission and somatosensory processing of noxious and innocuous cutaneous stimuli, while the role of NMDA receptors is restricted to longer latency synaptic components.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008465	Mechanoreceptors	Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.	Golgi Tendon Organ,Golgi Tendon Organs,Krause's End Bulb,Krause's End Bulbs,Mechanoreceptor,Mechanoreceptor Cell,Meissner's Corpuscle,Neurotendinous Spindle,Neurotendinous Spindles,Receptors, Stretch,Ruffini's Corpuscle,Ruffini's Corpuscles,Stretch Receptor,Stretch Receptors,Mechanoreceptor Cells,Bulb, Krause's End,Bulbs, Krause's End,Cell, Mechanoreceptor,Cells, Mechanoreceptor,Corpuscle, Meissner's,Corpuscle, Ruffini's,Corpuscles, Ruffini's,End Bulb, Krause's,End Bulbs, Krause's,Krause End Bulb,Krause End Bulbs,Krauses End Bulb,Krauses End Bulbs,Meissner Corpuscle,Meissners Corpuscle,Organ, Golgi Tendon,Organs, Golgi Tendon,Receptor, Stretch,Ruffini Corpuscle,Ruffini Corpuscles,Ruffinis Corpuscle,Ruffinis Corpuscles,Spindle, Neurotendinous,Spindles, Neurotendinous,Tendon Organ, Golgi,Tendon Organs, Golgi
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D010812	Physical Stimulation	Act of eliciting a response from a person or organism through physical contact.	Stimulation, Physical,Physical Stimulations,Stimulations, Physical
D011810	Quinoxalines		Quinoxaline
D005260	Female		Females
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.