The pontine A(5) noradrenergic cells which project to the spinal cord dorsal horn are reciprocally connected with the caudal ventrolateral medulla in the rat

• Type: Article in International Scientific Journal
• Date: 1997

Authors

Isaura Tavares (Author) FMUP; Deolinda Lima (Author) FMUP; Coimbra, A (Author) Other

Journal

Title: European Journal of Neuroscience

Vol. 9

Pages: 2452-2461

ISSN: 0953-816X

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 38 Citations

Scopus - 42 Citations

Other information

Authenticus ID: P-001-ABY

DOI: 10.1111/j.1460-9568.1997.tb01662.x

Abstract (EN): A disynaptic pathway linking the caudal ventrolateral medulla (VLM) to the spinal cord via the A(5) noradrenergic cell group of the pens has recently been described in the rat. In the present work, the projections of the A(5) to the VLM and to the spinal dorsal horn were studied with double-tracing techniques combined with immunostaining of the noradrenaline-synthesizing enzyme dopamine-beta-hydroxylase. Cholera toxin subunit B (CTb) injected into the VLM and fluoro-gold injected into the spinal dorsal horn produced double retrograde labelling of A(5) neurons immunoreactive for dopamine-beta-hydroxylase, which received appositions of fibre varicosities labelled anterogradely with CTb injected into the VLM. After injecting CTb into the A(5), retrogradely labelled neurons occurred in the VLM. These neurons were contacted by anterogradely labelled fibres from the A(5) group. These observations indicate that the VLM cells acting upon the A(5) spinally projecting neurons, which are likely to exert an alpha(2)-adrenoreceptor-mediated inhibition on the spinal cord, are targeted by collaterals of the A(5) spinal cord-bound axons. The A(5)-VLM pathway may be the anatomical substrate of a negative feedback circuit whereby the modulatory action of the VLM on the spinal cord is self-inhibited through activation of the A(5).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10