Different effects of anxiolytic agents, diazepam and 5-HT(1A) agonist tandospirone, on hippocampal long-term potentiation in vivo.
Benzodiazepines and 5-HT(1A) agonists have been widely used as anxiolytic agents. Some clinical reports document that 5-HT(1A) agonists induce memory impairment to a lesser degree than diazepam. In the present study, we compared the effects of diazepam and 5-HT(1A) agonist, tandospirone, on hippocampal long-term potentiation (LTP) in Schaffer collateral-CA1, mossy fiber-CA3 and perforant path-dentate gyrus synapses. In the diazepam-injected group, the reduction in LTP was observed in all three types of synapses, although the effective dose differed among these. In the tandospirone-injected group, no reduction in LTP was observed except in Schaffer-CA1 synapses. In addition, population spike amplitude was potentiated by tandospirone in mossy fiber-CA3 synapses in a dose-dependent manner. Thus, there was a discrepancy in the effects on hippocampal LTP between diazepam and tandospirone, possibly reflecting the reported clinical properties of these drugs, in that 5-HT(1A) partial agonists do not affect learning and memory, whereas diazepam impairs memory function.
Mori
K
K
Department of Pharmacology, Hokkaido University School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan. kimori@med.hokudai.ac.jp
Togashi
H
H
Kojima
T
T
Matsumoto
M
M
Ohashi
S
S
Ueno
K
K
Yoshioka
M
M
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D003975:Diazepam / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D054833:Isoindoles; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010879:Piperazines / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D014151:Anti-Anxiety Agents; D054833:Isoindoles; D010879:Piperazines; D011743:Pyrimidines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists; C055267:tandospirone; D003975:Diazepam