Growth-associated protein-43 (GAP-43) in the regenerating periodontal Ruffini endings of the rat incisor following injury to the inferior alveolar nerve.
Alterations in the levels of growth-associated protein 43 (GAP-43)-like immunoreactivity (-LI) were examined in the lingual periodontal ligament of the rat incisor following two types of injury (resection and crush) to the inferior alveolar nerve (IAN). In normal animals, GAP-43-like immunoreactive (IR) structures were observed as tree-like ramifications in the alveolar half of the lingual periodontal ligament of incisors. Under immunoelectron microscopy, GAP-43-LI appeared in the Schwann sheaths associated with periodontal Ruffini endings; neither cell bodies of the terminal Schwann cells nor axonal profiles showed GAP-43-LI. During regeneration of the periodontal Ruffini endings following resection of the IAN, GAP-43-LI appeared in the cytoplasm of the terminal Schwann cell bodies and axoplasm of the terminals. The distribution of GAP-43-LI in the Ruffini endings returned to almost normal levels on days 28 and 56 following the injury. The changes in the distribution of GAP-43-LI following the crush injury were similar to those following resection; however, expression of GAP-43-LI was slightly higher for the entire experimental period compared with the resection. The transient expression of GAP-43 in the terminal Schwann cells and axonal profiles of the periodontal Ruffini endings following nerve injury suggests that GAP-43 is closely associated with axon-Schwann cells interactions during regeneration.
Youn
S H
SH
Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, Suita, Osaka 565, Japan.
Maeda
T
T
Kurisu
K
K
Wakisaka
S
S
D000818:Animals; D019922:GAP-43 Protein / Q000032:analysis*; D007180:Incisor / Q000294:innervation*; D008297:Male; D008465:Mechanoreceptors / Q000737:chemistry*; D008854:Microscopy, Electron; D009409:Nerve Crush; D009411:Nerve Endings / Q000737:chemistry; D009416:Nerve Regeneration / Q000502:physiology*; D010513:Periodontal Ligament / Q000294:innervation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D061221:Trigeminal Nerve Injuries
D019922:GAP-43 Protein