Aquaporin 4: lack of mRNA expression in the rat regenerating muscle fiber under denervation.
The recently identified water channel aquaporin 4 is a major component of the orthogonal arrays observed with freeze-fracture electron microscopy. We examined the expression of aquaporin 4 mRNA and protein in rat regenerating muscle under innervated and denervated conditions. We found decreased sarcolemmal immunostaining of aquaporin 4 in denervated regenerating muscle as opposed to innervated muscle. Quantitative reverse transcription-polymerase chain reaction revealed that aquaporin 4 mRNA was expressed in the innervated regenerating muscle; whereas it was not expressed in denervated muscle. Thus, lack of aquaporin 4 protein may be due to lack of aquaporin 4 mRNA in the denervated regenerating muscle. We conclude that the nerve supply influences expression of aquaporin 4 at the mRNA level in regenerating muscle.
Jimi
T
T
Division of Neurology, Department of Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, 227-8501, Yokohama, Japan. jimi@poplar.ocn.ne.jp
Wakayama
Y
Y
Murahashi
M
M
Shibuya
S
S
Inoue
M
M
Hara
H
H
Matsuzaki
Y
Y
Uemura
N
N
D000818:Animals; D051401:Aquaporin 4; D020346:Aquaporins / Q000096:biosynthesis* / Q000235:genetics*; D008297:Male; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000235:genetics / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology
C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D020346:Aquaporins; D012333:RNA, Messenger