title: Monosynaptic excitation of preganglionic vasomotor neurons by subretrofacial neurons of the rostral ventrolateral medulla.
abstract: 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.
authors.affiliation: Physiologisches Institut, Christian Albrechts Universität, Kiel, FRG.
authors.forename: R M
authors.initials: RM
authors.lastname: McAllen
authors.forename: H J
authors.initials: HJ
authors.lastname: Häbler
authors.forename: M
authors.initials: M
authors.lastname: Michaelis
authors.forename: O
authors.initials: O
authors.lastname: Peters
authors.forename: W
authors.initials: W
authors.lastname: Jänig
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002415:Cats; D004594:Electrophysiology; D005154:Facial Nerve / Q000502:physiology*; D005260:Female; D005728:Ganglia, Sympathetic / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D014666:Vasomotor System / Q000166:cytology / Q000502:physiology*