Endogenous adenosine regulates the effects of low-frequency stimulation on the induction of long-term potentiation in CA1 neurons of guinea pig hippocampal slices.
A train of low-frequency afferent stimuli (LFS, 1 Hz, 1000 pulses), given 60 min prior to a tetanus (100 Hz, 100 pulses), suppresses the induction of long-term potentiation (LTP) in which a short-term potentiation decreases gradually back to the pre-tetanic level within 40-50 min (LTP suppression). We investigated the effects of adenosine A1 or A2 receptor antagonists (8-cyclopentyltheophylline (8-CPT) and CP-66713, respectively) on LTP suppression in CA1 neurons of guinea pig hippocampal slices. When the LFS was delivered in the presence of 8-CPT (1 microM), LTP suppression was not significantly affected. However, when LFS was delivered in the presence of CP-66713 (10 microM), LTP suppression was inhibited, leading to successful LTP induction. These results indicate that endogenous adenosine, acting via A2 receptors, is involved in the mechanism of LTP suppression.
Fujii
S
S
Department of Physiology, Yamagata University School of Medicine, Japan. sfujii@med.id.yamagata-u.ac.jp
Kuroda
Y
Y
Ito
K L
KL
Yoshioka
M
M
Kaneko
K
K
Yamazaki
Y
Y
Sasaki
H
H
Kato
H
H
D000241:Adenosine / Q000502:physiology*; D000344:Afferent Pathways; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D058915:Purinergic P1 Receptor Antagonists; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D011719:Pyrazines / Q000494:pharmacology*; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D013806:Theophylline / Q000031:analogs & derivatives* / Q000494:pharmacology
D058915:Purinergic P1 Receptor Antagonists; D011719:Pyrazines; D018047:Receptors, Purinergic P1; C053907:8-cyclopentyl-1,3-dimethylxanthine; C072107:CP 66713; D013806:Theophylline; D000241:Adenosine