The role of adenosine A(1) receptors in the interaction between amygdala and entorhinal cortex of kindled rats.
In this study the effect of adenosine A(1) receptors of the entorhinal cortex (EC) and amygdala on kindled seizures was investigated. Animals were kindled by daily electrical stimulation of amygdala (group 1) or EC (group 2). In the fully kindled animals, N(6)-cyclohexyladenosine (CHA), a selective A(1) receptor agonist, and 1,3-dimethyl-8-cyclopenthylxanthine (CPT), a selective A(1) receptor antagonist, were microinjected bilaterally into the EC (group 1) or amygdala (group 2). The seizure parameters were measured at 5, 15, 60 and 120 min post injection. Obtained data showed that in group 1, intra-EC microinjection of CHA at concentration of 10 microM reduced amygdala- and, EC-afterdischarge duration and stage 5 seizure duration at 5, 15, 60 and 120 min post drug injection. It also increased the latency to stage 4 seizure but no alteration was observed in seizure stage. At concentrations of 0.1 and 1 microM, CHA reduced only EC-afterdischarge duration at 5 and 15 min post drug infusion. Bilateral microinjection CPT at concentrations of 5 and 10 microM into the EC did not alter seizure parameters. Intra-EC microinjection of CPT (5 microM), 5 min before CHA (10 microM), blocked the anticonvulsant effects of CHA. On the other hand, in group 2 animals, intra-amygdala CHA (10, 50 and 100 microM) or CPT (5 and 10 microM) had no significant effect on seizure parameters of EC-kindled rats. These results suggest that adenosine A(1) receptors activation of the EC may have an inhibitory effect on amygdala-kindled seizures. But, despite of reciprocal interconnections between these two regions, activation of the A(1) receptors of the amygdala has no effect on EC-kindled seizures.
Mohammad-Zadeh
Mohammad
M
Department of Physiology, School of Medical Sciences, Tarbiat Modarres University, P.O. Box 14115-111, Tehran, Islamic Republic of Iran.
Amini
Azam
A
Mirnajafi-Zadeh
Javad
J
Fathollahi
Yaghoub
Y
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D058907:Adenosine A1 Receptor Agonists; D058916:Adenosine A1 Receptor Antagonists; D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology* / Q000528:radiation effects; D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004558:Electric Stimulation / Q000009:adverse effects; D018728:Entorhinal Cortex / Q000187:drug effects / Q000503:physiopathology* / Q000528:radiation effects; D007696:Kindling, Neurologic / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008845:Microinjections / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D043682:Receptor, Adenosine A1 / Q000502:physiology*; D012640:Seizures / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism*; D013997:Time Factors; D014970:Xanthines / Q000494:pharmacology
C112774:1,3-dimethyl-8-cyclopentylxanthine; D058907:Adenosine A1 Receptor Agonists; D058916:Adenosine A1 Receptor Antagonists; D043682:Receptor, Adenosine A1; D014970:Xanthines; C048599:N(6)-cyclopentyladenosine; D000241:Adenosine