Innervation of the renal vasculature of the toad (Bufo marinus)

Abstract

The innervation of the dorsal aorta and renal vasculature in the toad (Bufo marinus) has been studied with both fluorescence and ultrastructural histochemistry. The innervation consists primarily of a dense plexus of adrenergic nerves associated with all levels of the preglomerular vasculature. Non-adrenergic nerves are occasionally found in the renal artery, and even more rarely near the afferent arterioles. Many of the adrenergic nerve profiles in the dorsal aorta and renal vasculature are distinguished by high proportions of chromaffin-negative, large, filled vesicles. Close neuromuscular contacts are common in both the renal arteries and afferent arterioles. Possibly every smooth muscle cell in the afferent arterioles is multiply innervated. The glomerular capillaries and peritubular vessels are not innervated, and only 3-5% of efferent arterioles are accompanied by single adrenergic nerve fibres. Thus, nervous control of glomerular blood flow must be exerted primarily by adrenergic nerves acting on the preglomerular vasculature. The adrenergic innervation of the renal portal veins and efferent renal veins may play a role in regulating peritubular blood flow. In addition, glomerular and postglomerular control of renal blood flow could be achieved by circulating agents acting via contractile elements in the glomerular mesangial cells, and in the endothelial cells and pericytes of the efferent arterioles. Some adrenergic nerve profiles near afferent arterioles are as close as 70 nm to distal tubule cells, indicating that tubular function may be directly controlled by adrenergic nerves.

Mediolateral and rostrocaudal topographic organization of the sympathetic preganglionic cell pool in the spinal cord of Xenopus laevis

“…2) or that of the paravertebral chain ganglion cells (data not shown), we regarded the cell clusters as another, presumably postganglionic cell group of prevertebral sympathetic components. A similar postganglionic cell distribution has also been found in toads, Bufo marinus , and described as the renal ganglion cells (Morris and Gibbins,1983; Gibbins,1994). In Xenopus , sympathetic postganglionic cells that project to the pelvic organs have not been detected in the prevertebral position, but only within the paravertebral sympathetic chain attached to the ventral branches of the lumbosacral spinal nerves (Campbell et al,1994).…”

Ultrastructural Localisation of Substance P, Vasoactive Intestinal Polypeptide, Somatostatin and Neuropeptide Y Immunoreactivity in Perivascular Nerve Plexuses of the Gut

“…These immunoreactive nerve fibres were particularly dense and associated closely with the smooth muscle cells of the arteries and arterioles similar to the vascular innervation of other organs Uddman et al, 1981;Furness et al, 1982Furness et al, , 1983Morris and Gibbins, 1983;Yamada and Krause, 1983].…”

Renal Responses to Differential Rates of Blood Volume Expansion in the Toad, Bufo marinus

“…Therefore, sodium concentration indirectly determines the volume of the extracellular fluid. Hemodynamics (Guyton 1991), concentrations of electrolytes other than sodium (Persson and Persson 1981), hormones ( Sawyer 1951( Sawyer , 1957Pang et al 1980;Lang et al 1987), and the nervous system (Morris and Gibbins 1983) also influence renal function.…”

“…hormonal (Pang et al 1980), and neural influences in the afferent and efferent arterioles (Morris and Gibbins 1983); capillary permeability; capillary surface area; net pressure (hydrostatic and colloid osmotic) gradient between the glomerular capillary and capsular space; glomerular blood flow; and the number of actively filtering glomeruli (Forster 1942) The low ion concentration has two similar vascular effects (Guyton 1991).…”