Accuracy of reinnervation of rat internal intercostal muscles by their own segmental nerves

Abstract

The positions of internal intercostal motoneurons within their motor pool were studied, following reinnervation of the intercostal muscles by their original nerves. Six to 9 weeks after proximal nerve section in 10-d-old and adult rats, 0.1 microliter injections of wheat germ agglutinin (WGA)-HRP were made in the distal part of the reinnervated internal intercostal muscle. The corresponding region of the contralateral control muscle was also injected. The positions of the retrogradely labeled motoneurons were mapped in 100 microns transverse sections of thoracic spinal cord that had been stained for HRP according to the method of Mesulam (1982). In normal rats, motoneurons innervating distal muscle fibers are found largely in the more dorsal part of the internal intercostal motoneuron pool (Hardman and Brown, 1985). In adult rats, regenerated motor axons did not show any selectivity; distal muscle fibers were innervated by motoneurons whose cell bodies were distributed throughout the internal intercostal pool. However, in rats operated on at 10 d of age, distal intercostal muscle fibers were reinnervated by motoneurons that were distributed mainly in the dorsal part of the motor pool. These results support the view that positional signals may be of importance in organizing the distribution of axon terminals within muscles during development.

Spatial versus consumptive competition at polyneuronally innervated neuromuscular junctions

“…It is very clear that skeletal muscle is not a homogeneous tissue from the viewpoint of developing or regenerating motoneurones. For instance, motoneurones are evidently capable of making crude distinction between muscles on the basis of their position or segmental origin (Bennett & Lavidis, 1984;Wigston & Sanes, 1985;Donahue & English, 1987, 1989Hardman & Brown, 1987;Balice-Gordon & Thompson, 1988;Bennett & Ho, 1988;Laskowski & Sanes, 1988;Laskowski & High, 1989). Other data suggest that matching of motor terminals to muscle fibres of a pre-specified, complementary type is important in competition, both during postnatal development and following reinnervation in adults.…”

Context and Animal Behavior III: The Relationship Between Early Development and Evolutionary Persistence of Ground Squirrel Antisnake Behavior

“…Progressive differential gene expression would support the production of expanding neural networks congruent with the initial stabilization of segments of dendritic outgrowth and spine formation. Diffusible factors (soluble chemoattractant molecules in the extracellular matrix) released from target neurons are thought to play an important role in facilitating both the distal guidance and proximal homing of axonal outgrowth to specific neurons (Tessier-Lavigne, Placzek, Lumsden, Dodd, & Jessell, 1988) and perhaps axonal homing to specific dendritic areas (e.g., Hardman & Brown, 1987;Yamamoto, Kurotani, & Toyama, 1989). Along with these chemoattractants, the formation of plasma membrane oligosaccharides and carbohydrate-binding proteins would promote protein-protein and protein-carbohydrate interactions that facilitate cell recognition and adhesion (Hynes, Dodd, & Jessell, 1989;Schlosshauer, 1985).…”

Inaccurate projection of rat soleus motoneurons: A comparison of nerve repair techniques

“…Selective reinnervation has been reported to occur after transection of motor axons in neonatal rats, 2,14 larval anurans, 10 and adult urodeles. 29 Hardman and Brown 14 demonstrated that reinnervation of intercostal muscles of neonatal rats was topographically correct, whereas reinnervation in adult rats appeared to be random. Further, Gillespie et al 12 demonstrated nonselective innervation of rat lateral gastrocnemius and soleus muscles when the common nerve branch to these muscles was cut and sutured to the lateral gastrocnemius muscle.…”