Short-term synaptic plasticity in layer II/III of the rat anterior cingulate cortex.
Recent in vivo electrophysiological studies in our laboratory demonstrated medial thalamus (MT) induced short-term facilitation in the middle layers of the anterior cingulate cortex (ACC). The aim of the present study was to investigate different forms of short-term plasticity (STP) in layer II/III of the ACC in an in vitro slice preparation. Extracellular field potentials in layer II/III consisting of an early component (fAP) and a late component (fPSP) were activated by electrical stimulation of the deep layers. The fPSP and intracellularly recorded excitatory post-synaptic potential (EPSP) could be facilitated by paired-pulse stimulation at a low frequency (0.033Hz, pulse interval 20-400ms). An initial facilitation and subsequent depression were obtained when high frequency (12.5, 25 and 50Hz) tetanus stimulations were applied to the ACC slice. A post-tetanic augmentation 30s in duration was also observed. The effects of tetanic stimulation were altered in the presence of an increased or a decreased calcium concentration. Application of omega-conotoxin GVIA (CTX) in normal calcium concentration conditions decreased overall responses during tetanic stimulation similar to reducing calcium exposure. However CTX application did not increase paired-pulse facilitation (PPF) as is seen under low calcium conditions. These results indicate that calcium is involved in the formation of certain features of STP in layer II/III of the ACC and that N-type calcium channels contribute to some, but not all, components of these plastic changes. Two-site electrical stimulation testing showed that two separate presynaptic inputs can produce short-term facilitation. Our findings implicate a post-synaptic mechanism in STP in layer II/III of the ACC.
Lee
Chia-Ming
CM
Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan, ROC.
Sylantyev
Sergiy
S
Shyu
Bai-Chuang
BC
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020864:Calcium Channels, N-Type / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D003463:Cues; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D004594:Electrophysiology; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D008239:Lysine / Q000031:analogs & derivatives; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; C013411:biocytin; D008239:Lysine