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Effects of hypoglossal and facial nerve injuries on milk‐suckling
Author(s) -
Fujita K.,
Yokouchi K.,
Fukuyama T.,
Fukushima N.,
Kawagishi K.,
Moriizumi T.
Publication year - 2006
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/j.ijdevneu.2005.11.009
Subject(s) - hypoglossal nerve , tongue , trunk , medicine , facial nerve , anatomy , biology , pathology , ecology
Functional roles of the perioral anatomical structures involved in breastfeeding were examined in newborn rat pups in which the hypoglossal (XII) and facial (VII) nerves had been resected at the neonatal stage. The XII nerve controls tongue movement and is comprised of two functionally distinct branches: the medial branch related to protrusion of the tongue and the lateral branch related to its retraction. Newborn rat pups with bilateral resection of either of the XII nerve components (main trunk: XII‐trunk; medial branch: XII‐med; lateral branch: XII‐lat) failed to suckle milk and did not survive. Unilateral XII nerve‐resected neonates showed different milk‐suckling capabilities, which thus resulted in differences in survival rate (XII‐trunk: 38%; XII‐med: 24%; XII‐lat: 92%) and postnatal growth during the postnatal 3 weeks until P21. Unilateral and bilateral resections of the VII nerve innervating the buccolabial musculature produced lowered suckling capabilities and retarded postnatal growth, although all pups showed 100% survival. The results indicate a crucial role of the tongue, especially of protruding muscular elements innervated by the XII‐med nerve, in breastfeeding. The results also indicate differential effects of the VII and XII nerve components on suckling capability, survival, and postnatal growth of newborn rat pups.