4-Aminopyridine-induced spreading depression episodes in immature hippocampus: Developmental and pharmacological characteristics

摘要: Spontaneous spreading depression episodes were studied in CA1 and CA3 areas of immature hippocampal slices (two to 30 days postnatally) during 4-aminopyridine (SO μM) perfusion. Spreading occurred the area 34% all tested postnatally). The duration frequency field potentials changed with development. In area, their decreased from 169 ± 22s (n = 17, postnatal two 10) 55 7s 10, 21–30), rate occurrence increased four per hour ( 0.0011 0.0001Hz, n 11, 6.5 (0.0018 0.0003Hz,n 8, while amplitude remained stable (10–30 mV). d.c. potential shift originated closer than CA3. Furthermore, had greater magnitude (amplitude duration) CA1. depressions reversibly blocked by N-methyl-d-aspartate receptor antagonist 3,3-(2-carboxy-piperazine-4-yl)-propyl-1-phosphonate (CPP, 1–5 μM, 15), but not affected 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX, 2–5 μm, 11), which is a non-N-methyl-d-aspartate antagonist. GABAA bicuculline methiodide (3–10 initially favored then 79% 16). addition, impaired propagation 4-Aminopyridine also induced appearance other types spontaneous activity, such as ictal interictal-like epileptiform discharges. effects 3,3-(2-carboxy-piperazine-4-yl)-propyl-1-phosphonate, on activity opposite those depression. Our findings demonstrate that can occur early postnatally characteristics this phenomenon change maturation. These results indicate 4-aminopyridine-induced are mediated activation different excitatory amino acid receptors. Finally, influenced blockade receptor.