Effects of cholecystokinin tetrapeptide (CCK(4)) and of anxiolytic drugs on GABA outflow from the cerebral cortex of freely moving rats.
The effect of cholecystokinin tetrapeptide (CCK(4)) and of different anxiolytic drugs on GABA outflow from the cerebral cortex was investigated in freely moving rats, by using the epidural cup technique. CCK(4) (3-30 microg/kg, i.p.) increased GABA outflow and induced objective signs of anxiety. These neurochemical and behavioral responses were prevented by the CCK(B) antagonist GV150013 at 0.1 microg/kg (i.p.). At higher doses (up to 30 microg/kg) this compound per se reduced GABA release and caused sedation, suggesting the presence of a CCKergic positive tonic modulation on GABA interneurons. Similarly the GABA(A) receptors modulator, diazepam (2mg/kg, i.p.) and the 5-HT(1A) agonist buspirone (3mg/kg, i.p.) reduced GABA outflow and caused the expected behavioral effects (reduced muscle tone, mild 5-HT syndrome) which were prevented by the respective, selective antagonists, flumazenil (1mg/kg, i.p.) and NAN-190 (3mg/kg, i.p.). These findings support the idea that GV150013, diazepam and buspirone inhibit GABAergic cortical activity, through the respective receptors. This neurochemical effect may represent the end-effect of various anxiolytic compounds affecting the cortical circuitry.
Siniscalchi
A
A
Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy.
Rodi
D
D
Cavallini
S
S
Marino
S
S
Ferraro
L
L
Beani
L
L
Bianchi
C
C
D000218:Adamantane / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D002065:Buspirone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D003975:Diazepam / Q000494:pharmacology; D004824:Epidural Space; D005260:Female; D005442:Flumazenil / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000187:drug effects; D010671:Phenylurea Compounds / Q000037:antagonists & inhibitors / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D044263:Receptors, Serotonin, 5-HT1; D012701:Serotonin / Q000378:metabolism; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013758:Tetragastrin / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D014151:Anti-Anxiety Agents; C111554:GV 150013X; D006993:Hypnotics and Sedatives; D009125:Muscle Relaxants, Central; D009419:Nerve Tissue Proteins; D010671:Phenylurea Compounds; D010879:Piperazines; D011963:Receptors, GABA-A; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D013758:Tetragastrin; C058895:1-(2-methoxyphenyl)-4-(4-(2-phthalimido)butyl)piperazine; D012701:Serotonin; D005442:Flumazenil; D005680:gamma-Aminobutyric Acid; D000218:Adamantane; D003975:Diazepam; D002065:Buspirone