Effects of phencyclidines on signal transfer from the entorhinal cortex to the hippocampus in rats.
The information transfer from the superficial layers of the entorhinal cortex (EC) to the hippocampus is regulated in a frequency dependent manner. Phencyclidine and related compounds such as MK-801 produce psychotic symptoms that closely resemble schizophrenia. We studied the effects of systemic administration of MK-801 on the signal transfer from the EC layer III to the hippocampal area CA1. High frequency (above 10 Hz) activation of the bi-synaptic entorhinal input in control animals results in a strong suppression of the field potentials in the stratum lacunosum-moleculare of the area CA1. In contrast, in MK-801 pretreated rats the field response was less reduced. The field potential responses evoked in these two groups of animals by high-frequency activation of the monosynaptic input were similar suggesting selective alterations in layer III of the medial EC. We suggest, that MK-801 causes disinhibition of layer III projection cells and, therefore, may cause strong, pathological activation of direct layer III-CA1 pathway.
Dugladze
Tamar
T
Johannes-Müller-Institute of Physiology at the Charité, Humboldt University, Berlin, Tucholskystrasse 2, 10117 Berlin, Germany.
Lepsveridze
Eka
E
Breustedt
Jörg
J
Kehrer
Colin
C
Heinemann
Uwe
U
Gloveli
Tengis
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D018728:Entorhinal Cortex / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D006624:Hippocampus / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D009431:Neural Conduction / Q000187:drug effects*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D010622:Phencyclidine / Q000494:pharmacology*; D051381:Rats
D018691:Excitatory Amino Acid Antagonists; D016291:Dizocilpine Maleate; D010622:Phencyclidine