ACTH peptides as organizers of neuronal patterns in development: maturation of the XXXX neuromuscular junction as seen by scanning electron microscopy.

@entity35 @entity1239 @entity14480
SEM was used to visualize the normal postnatal development of the neonatal @entity35 neuromuscular junction (nmj). Maturational changes evoked by ACTH/MSH 4-10 (10 micrograms/kg/day IP) or ACTH/MSH 4-9 ( @entity14480 ) (0.01 microgram/kg/day IP) were compared to controls and to pups treated with @entity1239 during prenatal and postnatal life, or only during the gestation period. Pregnant females received 0.25 mg/kg 2X daily IP; neonates 0.05 mg/kg/day SC. The Desaki and Uehara and Fahim et al. methods revealed the nmj on the extensor digitorum muscle to be covered by a delicate drapery of postjunctional folds that surround the immature endplate region. By the second week of postnatal life, these folds become more complex and cover a larger area. Upon maturation the folds descend and invaginate into the muscle fiber. Peptide treatment with either ACTH/MSH 4-10 or ACTH/MSH 4-9 accelerates maturation of the endplate as demonstrated by the increased convolutions of the folds. Similar effects follow @entity1239 administration. The observed changes in morphology of the developing nmj subjected to @entity1239 may be mediated through @entity1239 -evoked ACTH release.
