Alnespirone and buspirone have anxiolytic-like effects in a conflict procedure in rats by stimulating 5-HT(1A) receptors.
We studied the anxiolytic-like activity of alnespirone and buspirone, two 5-HT(1A) receptor agonists, in a modified Geller-Seifter conflict model, and examined the role of 5-HT(1A) receptors by studying whether WAY-100635, a selective antagonist at these receptors, blocked their effects. Administered s.c. 30 minutes before testing, 0.5 and 1mg/kg alnespirone significantly increased punished responding, whereas lower doses (0.125 and 0.25 mg/kg) had no effect. At 1mg/kg, alnespirone significantly reduced the rates of unpunished responding. One dose of buspirone (1mg/kg) significantly increased punished responding and reduced unpunished responding. Lower doses were ineffective. Administered s.c. 40 minutes before testing, WAY-100635 had no effect on any parameter but completely antagonized the effects of alnespirone (1mg/kg) and buspirone (1mg/kg) on punished responding. The ability of buspirone to reduce unpunished responding was not antagonized by WAY-100635, probably reflecting a sedative effect of buspirone due to dopamine D2 receptor blockade. The results suggest that alnespirone and buspirone have anxiolytic-like activity in a conflict procedure by stimulating 5-HT(1A) receptors, presumably at a presynaptic level. Like buspirone, alnespirone may have useful effects in the treatment of anxiety disorders.
Cervo
L
L
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Munoz
C
C
Bertaglia
A
A
Samanin
R
R
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D002065:Buspirone / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D003220:Conflict, Psychological; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects*; D044263:Receptors, Serotonin, 5-HT1; D012055:Reinforcement Schedule; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013141:Spiro Compounds / Q000494:pharmacology*
D014151:Anti-Anxiety Agents; D010879:Piperazines; D011725:Pyridines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D013141:Spiro Compounds; C075319:alnespirone; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D002065:Buspirone