McAllen R M, Häbler H J, Michaelis M, Peters O, Jänig W
Physiologisches Institut, Christian Albrechts Universität, Kiel, FRG.
Brain Res. 1994 Jan 21;634(2):227-34. doi: 10.1016/0006-8993(94)91925-9.
Extracellular single unit recordings were made from barosensitive neurons in the subretrofacial nucleus (SRF) of the rostral ventrolateral medulla in chloralose-anaesthetised cats. At the same time, single preganglionic neuron activity was recorded from filaments of the cervical sympathetic trunk (CST); barosensitive units were selected for study. Evidence for monosynaptic connections between the two neuron groups was sought by cross-correlation analysis of their ongoing activity. Cross-correlograms of 16/16 SRF/CST neuron pairs showed a broad peak (100-200ms wide), reflecting the synchronizing action of arterial baroreceptors on both neurons' activity. Two of the 16 cross-correlograms additionally showed a robust, statistically significant, narrow peak of a single 2 ms bin width, providing the first physiological demonstration that ventrolateral medullary neurons monosynaptically excite preganglionic sympathetic neurons. Deductions are made about the strength, convergence and divergence of the connection.
