Characteristics of muscarinic cholinergic, γ-aminobutyric acid_A and phencyclidine receptors in spontaneously epileptic rats; in vitro quantitative autoradiographic analysis

Characteristics of muscarinic cholinergic (mACh), γ-aminobutyric acid_A (GABA_A) and phencyclidine (PCP) receptors in the spontaneously epileptic rats (SER), which exhibit both absence-like seizures and tonic convulsion, were examined using in vitro quantitative autoradiography. Computer analysis using autoradiographic technique revealed that the amount of the specific binding of [³H]quinuclidinyl benzilate (QNB) to mACh receptors in the striatum of SER was more than that of zitter rats, not exhibiting both seizures and convulsion. However, the specific bindings of [³H]muscimol and [³H]N-(2-thienyl)cyclohexyl)3,4-piperidine (TCP) to GABA_A and PCP receptors, respectively, of SER were not different from those of zitter rats in various regions tested. These results suggest that hyperfunction of mACh receptors in the striatum is involved in the appearance of absence-like seizures and tonic convulsion of SER.