Gamma-aminobutyric acidB, but not gamma-aminobutyric acidA receptor activation, inhibits electrically evoked substance P-like immunoreactivity release from the rat spinal cord in vitro. 1993

M Malcangio, and N G Bowery
Department of Pharmacology, School of Pharmacy, London, United Kingdom.

Substance P (SP) is believed to be a neuromodulator of primary afferent neurons involved in nociception. Because baclofen alters nociception at the level of the spinal cord and the receptor it activates (gamma-aminobutyric acidB; GABAB) is located on presynaptic terminals, we examined whether this agent and GABA could influence the electrically evoked release of SP from rat spinal cord in vitro. The calcium- and tetrodotoxin-dependent release of SP was inhibited completely by GABA (IC50, 165 +/- 17.8 microM) and (-)-baclofen (IC50, 0.8 +/- 0.2 microM) in a dose-dependent manner. The effect of baclofen was stereospecific, (+)-baclofen being approximately 1000 times weaker then the (-)-isomer. The GABAA agonist, isoguvacine (10-100 microM), did not reduce SP release but, if anything, tended to increase SP release. GABA- and (-)-baclofen-induced inhibition of electrically evoked SP release was antagonized by the GABAB antagonists, CGP 35348 and CGP 36742 (10-100 microM). Bicuculline (300 microM) did not affect GABA-inhibition of SP release. These observations suggest that GABAB receptors are likely to mediate the effect of GABA and baclofen on primary afferent terminals. In view of the presence of GABAB receptors in the dorsal horn of the rat spinal cord on slow conducting primary afferent terminals which contain SP, we suggest that the inhibition of the neuropeptide release may be one mechanism to explain baclofen-induced antinociception within the spinal cord.

UI MeSH Term Description Entries
D009943 Organophosphorus Compounds Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS. Organophosphorus Compound,Organopyrophosphorus Compound,Organopyrophosphorus Compounds,Compound, Organophosphorus,Compound, Organopyrophosphorus,Compounds, Organophosphorus,Compounds, Organopyrophosphorus
D011963 Receptors, GABA-A Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop. Benzodiazepine-Gaba Receptors,GABA-A Receptors,Receptors, Benzodiazepine,Receptors, Benzodiazepine-GABA,Receptors, Diazepam,Receptors, GABA-Benzodiazepine,Receptors, Muscimol,Benzodiazepine Receptor,Benzodiazepine Receptors,Benzodiazepine-GABA Receptor,Diazepam Receptor,Diazepam Receptors,GABA(A) Receptor,GABA-A Receptor,GABA-A Receptor alpha Subunit,GABA-A Receptor beta Subunit,GABA-A Receptor delta Subunit,GABA-A Receptor epsilon Subunit,GABA-A Receptor gamma Subunit,GABA-A Receptor rho Subunit,GABA-Benzodiazepine Receptor,GABA-Benzodiazepine Receptors,Muscimol Receptor,Muscimol Receptors,delta Subunit, GABA-A Receptor,epsilon Subunit, GABA-A Receptor,gamma-Aminobutyric Acid Subtype A Receptors,Benzodiazepine GABA Receptor,Benzodiazepine Gaba Receptors,GABA A Receptor,GABA A Receptor alpha Subunit,GABA A Receptor beta Subunit,GABA A Receptor delta Subunit,GABA A Receptor epsilon Subunit,GABA A Receptor gamma Subunit,GABA A Receptor rho Subunit,GABA A Receptors,GABA Benzodiazepine Receptor,GABA Benzodiazepine Receptors,Receptor, Benzodiazepine,Receptor, Benzodiazepine-GABA,Receptor, Diazepam,Receptor, GABA-A,Receptor, GABA-Benzodiazepine,Receptor, Muscimol,Receptors, Benzodiazepine GABA,Receptors, GABA A,Receptors, GABA Benzodiazepine,delta Subunit, GABA A Receptor,epsilon Subunit, GABA A Receptor,gamma Aminobutyric Acid Subtype A Receptors
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
D005680 gamma-Aminobutyric Acid The most common inhibitory neurotransmitter in the central nervous system. 4-Aminobutyric Acid,GABA,4-Aminobutanoic Acid,Aminalon,Aminalone,Gammalon,Lithium GABA,gamma-Aminobutyric Acid, Calcium Salt (2:1),gamma-Aminobutyric Acid, Hydrochloride,gamma-Aminobutyric Acid, Monolithium Salt,gamma-Aminobutyric Acid, Monosodium Salt,gamma-Aminobutyric Acid, Zinc Salt (2:1),4 Aminobutanoic Acid,4 Aminobutyric Acid,Acid, Hydrochloride gamma-Aminobutyric,GABA, Lithium,Hydrochloride gamma-Aminobutyric Acid,gamma Aminobutyric Acid,gamma Aminobutyric Acid, Hydrochloride,gamma Aminobutyric Acid, Monolithium Salt,gamma Aminobutyric Acid, Monosodium Salt
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
D001418 Baclofen A GAMMA-AMINOBUTYRIC ACID derivative that is a specific agonist of GABA-B RECEPTORS. It is used in the treatment of MUSCLE SPASTICITY, especially that due to SPINAL CORD INJURIES. Its therapeutic effects result from actions at spinal and supraspinal sites, generally the reduction of excitatory transmission. Baclophen,Chlorophenyl GABA,Apo-Baclofen,Atrofen,Ba-34,647,Ba-34647,Baclofen AWD,Baclofène-Irex,Baclospas,CIBA-34,647-BA,Clofen,Gen-Baclofen,Genpharm,Lebic,Lioresal,Liorésal,Nu-Baclo,PCP-GABA,PMS-Baclofen,beta-(Aminomethyl)-4-chlorobenzenepropanoic Acid,beta-(p-Chlorophenyl)-gamma-aminobutyric Acid,AWD, Baclofen,Apo Baclofen,ApoBaclofen,Ba34,647,Ba34647,Baclofène Irex,BaclofèneIrex,CIBA34,647BA,GABA, Chlorophenyl,Gen Baclofen,GenBaclofen,Nu Baclo,NuBaclo,PMS Baclofen,PMSBaclofen
D013116 Spinal Cord A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER. Coccygeal Cord,Conus Medullaris,Conus Terminalis,Lumbar Cord,Medulla Spinalis,Myelon,Sacral Cord,Thoracic Cord,Coccygeal Cords,Conus Medullari,Conus Terminali,Cord, Coccygeal,Cord, Lumbar,Cord, Sacral,Cord, Spinal,Cord, Thoracic,Cords, Coccygeal,Cords, Lumbar,Cords, Sacral,Cords, Spinal,Cords, Thoracic,Lumbar Cords,Medulla Spinali,Medullari, Conus,Medullaris, Conus,Myelons,Sacral Cords,Spinal Cords,Spinali, Medulla,Spinalis, Medulla,Terminali, Conus,Terminalis, Conus,Thoracic Cords
D013373 Substance P An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses. Euler-Gaddum Substance P,Hypothalamic Substance P,SP(1-11),Euler Gaddum Substance P,Substance P, Euler-Gaddum,Substance P, Hypothalamic
D014179 Neurotransmitter Uptake Inhibitors Drugs that inhibit the transport of neurotransmitters into axon terminals or into storage vesicles within terminals. For many transmitters, uptake determines the time course of transmitter action so inhibiting uptake prolongs the activity of the transmitter. Blocking uptake may also deplete available transmitter stores. Many clinically important drugs are uptake inhibitors although the indirect reactions of the brain rather than the acute block of uptake itself is often responsible for the therapeutic effects. Reuptake Inhibitors, Neurotransmitter,Transmitter Uptake Inhibitors, Neuronal,Inhibitors, Neurotransmitter Uptake,Uptake Inhibitors, Neurotransmitter,Inhibitors, Neurotransmitter Reuptake,Neurotransmitter Reuptake Inhibitors
D017208 Rats, Wistar A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain. Wistar Rat,Rat, Wistar,Wistar Rats

Related Publications

M Malcangio, and N G Bowery
March 1989, The Journal of pharmacology and experimental therapeutics,
M Malcangio, and N G Bowery
December 1998, British journal of pharmacology,
M Malcangio, and N G Bowery
July 1993, Regulatory peptides,
M Malcangio, and N G Bowery
January 1991, Neuroscience,
Copied contents to your clipboard!