Isoflurane differentially modulates inhibitory and excitatory synaptic transmission to the solitary tract nucleus

Abstract

BACKGROUND: Isoflurane anesthesia produces cardiovascular and respiratory depression, although the specific mechanisms are not fully understood. Cranial visceral afferents, which innervate the heart and lungs, synapse centrally onto neurons within the medial portion of the nucleus tractus solitarius (NTS). Isoflurane modulation of afferent to NTS synaptic communication may underlie compromised cardiorespiratory reflex function. METHODS: Adult rat hindbrain slice preparations containing the solitary tract (ST) and NTS were used. Shocks to ST afferents evoked excitatory postsynaptic currents with low-variability (SEM <200 mus) latencies identifying neurons as second order. ST-evoked and miniat..