Experiments on partially deneurotized nerves. II. Hypertrophy of residual fibers

✍ Scribed by Edds, Mac V.

• Publisher: John Wiley and Sons
• Year: 1949
• Tongue: English
• Weight: 940 KB
• Volume: 112
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401120105

✦ Synopsis

Recent studies have emphasized the reciprocal, trophic relationship between adult neurons and their end or& oans. Peripheral tissues, long known to depend on their innervation f o r structural and functional integrity, in turn influence the nerve cells which supply them. When severed from their terminal connections, axons undergo an atrophy which may become extreme if reconnection is permanently prevented (Weiss and Taylor, '44; Sanders and Young ,'45; Weiss, Edds and Cavanaugh, '45 ; Sanders and Young, '46 ; Aitken, Sharman and Young, '47; Aitken, '49). The effect also extends to the cell body (Howe and Bodian, '41; Cavanaugh, '48). Complete disconnection is not essential ; following constriction of an axon, the centrifugal convection of axoplasm proximal to the constriction -and presumably the synthesis of new axoplasm in its cell bodyoccurs at a reduced rate (TVeiss and Hiscoe, '48 ; but cf. Duncan, '48). Moreover, a functionally inappropriate end organ is not an adequate substitute for a normal one : somatic fibers regenerating into visceral endings do not regain normal dimensions (Simpson and Young, '45) ; sensory fibers forced to enter muscles and motor fibers shunted into the skin remain undersized (Weiss et al., '45; Aitken et al., '47).

The effect of increasing the number of their peripheral connections on the size of iierve cells remains to be determined.