Antagonistic effects of S 22153, a new mt1 and MT2 receptor ligand, on the neophobia-reducing properties of melatonin in BALB/c mice.
When exposed to a free-exploratory situation, BALB/c mice are well known to exhibit strong avoidance responses toward unfamiliar places (neophobia). Because melatonin was found to significantly reduce neophobia in BALB/c mice, it seemed interesting to examine potential antagonistic effects of S 22153, a new melatonin mt1 and MT2 receptor ligand, on the neophobia-reducing properties of melatonin in BALB/c mice confronted with the free-exploratory paradigm. S 22153 was able to block, in a dose-dependent manner, the anxiolytic-like properties of melatonin when it was administered 5 min before melatonin. The antagonistic effects of S 22153 persisted when the drug was administered 2 or 4 h before melatonin, and were almost abolished when it was administered 6 h before melatonin. These results suggest that the anxiolytic-like effects of melatonin on the neophobic responses in BALB/c mice are mediated by mt1 and/or MT2 receptors.
Kopp
C
C
Laboratoire d'Ethologie et de Neurobiologie, Strasbourg, France.
Vogel
E
E
Rettori
M C
MC
Delagrange
P
P
Renard
P
P
Lesieur
D
D
Misslin
R
R
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy* / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects; D008024:Ligands; D008297:Male; D008550:Melatonin / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009043:Motor Activity / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000187:drug effects*; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects*; D044094:Receptors, Melatonin; D013876:Thiophenes / Q000494:pharmacology*; D013997:Time Factors
D014151:Anti-Anxiety Agents; D008024:Ligands; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D044094:Receptors, Melatonin; C120267:S 22153; D013876:Thiophenes; D008550:Melatonin