Biomaterial Database

Fast synaptic transmission mediated by alpha-bungarotoxin-sensitive nicotinic acetylcholine receptors in lamina X neurones of neonatal rat spinal cord. 2002

A Bradaïa, and J Trouslard

Laboratoire de Neurophysiologie Cellulaire et Intégrée, UMR 7519 CNRS/ULP, 21 rue R. Descartes, 67084 Strasbourg Cedex, France.

Using patch clamp recordings on neonatal rat spinal cord slices, we have looked for the presence of alpha-bungarotoxin-sensitive nicotinic ACh receptors (nAChRs) on sympathetic preganglionic neurones (SPNs) surrounding the central canal of the spinal cord (lamina X) and examined whether they were implicated in a fast cholinergic synaptic transmission. SPNs were identified either by their morphology using biocytin in the recording electrode and/or by antidromic stimulation of the ventral rootlets. The selective alpha7-containing nAChR (alpha7*nAChR) agonist choline (10 mM) induced a fast, rapidly desensitizing inward current, which was fully blocked by alpha-bungarotoxin (alpha-BgT; 50 nM) and strychnine (1 microM), two antagonists of alpha7*nAChRs. The I-V relationship of the choline-induced current showed a strong inward-going rectification. Electrically evoked excitatory postsynaptic currents (eEPSCs) could be recorded. At -60 mV, eEPSCs peaked at -26.2 pA and decayed monoexponentially with a mean time constant of 8.5 ms. The current-voltage relationship for eEPSCs exhibited a strong inward rectification and a reversal potential close to 0 mV, compatible with a non-selective cationic current. The appearance of eEPSCs was entirely suppressed by the application of 100 microM ACh or nicotine. Choline (10 mM) and 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP; 100 microM) both reduced the amplitude of eEPSCs, whereas cytisine (100 microM) had no effect. Strychnine (1 microM) and alpha-BgT (50 nM) both suppressed the eEPSCs. Blocking the P2X purinergic and 5-HT(3) receptors had no effect on eEPSCs. DMPP induced four types of current, which differed in their onset and desensitization rate. The most frequently encountered responses were insensitive to the action of strychnine and alpha-BgT, and were reproduced by ACh and nicotine but not by cytisine. We conclude that SPNs of the lamina X express several classes of nAChRs and in particular alpha-BgT-sensitive nAChRs. This is the first demonstration in a mammalian spinal cord preparation of a fast cholinergic neurotransmission in which alpha-BgT-sensitive nicotinic receptors are involved.

UI	MeSH Term	Description	Entries
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
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D011978	Receptors, Nicotinic	One of the two major classes of cholinergic receptors. Nicotinic receptors were originally distinguished by their preference for NICOTINE over MUSCARINE. They are generally divided into muscle-type and neuronal-type (previously ganglionic) based on pharmacology, and subunit composition of the receptors.	Nicotinic Acetylcholine Receptors,Nicotinic Receptors,Nicotinic Acetylcholine Receptor,Nicotinic Receptor,Acetylcholine Receptor, Nicotinic,Acetylcholine Receptors, Nicotinic,Receptor, Nicotinic,Receptor, Nicotinic Acetylcholine,Receptors, Nicotinic Acetylcholine
D002038	Bungarotoxins	Neurotoxic proteins from the venom of the banded or Formosan krait (Bungarus multicinctus, an elapid snake). alpha-Bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterized, the alpha being similar to the large, long or Type II neurotoxins from other elapid venoms.	alpha-Bungarotoxin,beta-Bungarotoxin,kappa-Bungarotoxin,alpha Bungarotoxin,beta Bungarotoxin,kappa Bungarotoxin
D002794	Choline	A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.	Bursine,Fagine,Vidine,2-Hydroxy-N,N,N-trimethylethanaminium,Choline Bitartrate,Choline Chloride,Choline Citrate,Choline Hydroxide,Choline O-Sulfate,Bitartrate, Choline,Chloride, Choline,Choline O Sulfate,Citrate, Choline,Hydroxide, Choline,O-Sulfate, Choline
D004246	Dimethylphenylpiperazinium Iodide	A selective nicotinic cholinergic agonist used as a research tool. DMPP activates nicotinic receptors in autonomic ganglia but has little effect at the neuromuscular junction.	DMPP,1,1-Dimethyl-4-phenylpiperazine Iodide,Dimethylphenylpiperazinium,1,1 Dimethyl 4 phenylpiperazine Iodide,Iodide, 1,1-Dimethyl-4-phenylpiperazine,Iodide, Dimethylphenylpiperazinium
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
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