Using the isolated in vitro rat spinal cord, Dougherty et al (2001; SFN Abst) showed that spike broadening following application of the convulsants TEA & 4AP resulted in the emergence of novel forms of synchronous bursting throughout the spinal neuraxis: (1) bursting mediated via electrical transmission, independent of ionotropic receptors, and (2) bursting mediated chemically in the absence of external Ca2+ but requiring release from internal Ca2+ stores. The present study further characterized these bursting patterns. Motor activity was recorded from various ventral roots in the isolated neonatal rat spinal cord. (1) Synchronous activity induced by bicuculline/strychnine/5-HT but blocked by the glutamate receptor blockers CNQX/APV re-emerged after applying TEA/4AP. Activity block by carbenoxolone implicated electrical coupling. Here, we support this conclusion by showing that blockade of all known voltage-gated Ca2+ channels does not block the TEA/4AP evoked synchronous activity. This bursting was blocke...