Lateralisation of projections from the rostral ventrolateral medulla to sympathetic preganglionic neurons in the rat

摘要: Spinally projecting sympathoexcitatory neurons in the rostral ventrolateral medulla (RVLM), synapse with sympathetic preganglionic (SPN) and regulate activity of nerves that control heart, blood pressure adrenal (AM). However, degree lateralization bulbospinal projections to SPN innervating specific targets is poorly understood. Three approaches were used this study. Anterograde tracer was iontophoresed into a pressor site RVLM (left or right) retrograde injected superior cervical ganglion (SCG, AM (left). Close appositions between anterogradely labelled axons retrogradely SCG- AM-SPN counted. Projections SCG bilateral. markedly ipsilateral. In second part, tracers unilaterally region intermediolateral cell column at spinal segment T2 T8 on one side number The results from each level injection similar showing approximately 63-64% Responses glutamate microinjection nerve (left) measured. ratio responses same even when different sides injected. anterograde data strongly suggest are predominantly Although other experimental also attempted investigate lateralization, target functionally heterogeneous pools may mask ipsilateral projection AM. Similarly, chemical stimulation will excite not only monosynaptic but polysynaptic predominant