Pre- and postnatal development of the catecholamine innervation of the hypoglossal nucleus in the rat: an immunocytochemical study.
The pre- and postnatal development of the catecholamine (CA) innervation to the hypoglossal nucleus (nXII) in the rat was investigated immunocytochemically with antisera to tyrosine hydroxylase (TH). Immunoreactive profiles positive for TH were first identified in nXII on gestational day (GD) 16. By GD 18, the adult-like distribution pattern was evident, characterized by the preferential targeting of the ventromedial region of nXII, but this pattern was not consistently found in all fetuses until GD 19. From GD 19 to postnatal day (PD) 180, the overall density of TH immunoreactivity, particularly in the ventromedial region, increased with further growth and maturation of nXII. These results establish the early prenatal CA innervation of nXII and support the hypothesis that CA are important in regulating motor tongue behavior in the newborn. Moreover, because the ventral compartment of nXII contains motoneurons that innervate protrusor muscles of the tongue, and tongue protrusor mechanisms play an essential role in suckling, deglutition, and respiratory (maintaining a patent upper airway) behaviors, it is further proposed that the CA innervation of nXII is critical to the survival of the newborn.
Aldes
L D
LD
Department of Structural and Cellular Biology, University of South Alabama, Mobile 36688, USA. laldes@jaguar1.usouthal.edu
Bartley
K
K
Royal
K
K
Dixon
A
A
Chronister
R B
RB
D000818:Animals; D002395:Catecholamines / Q000502:physiology*; D003720:Densitometry; D005260:Female; D007002:Hypoglossal Nerve / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D007150:Immunohistochemistry; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014059:Tongue / Q000201:enzymology / Q000254:growth & development / Q000294:innervation; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase