Detection of hypothalamic activation by manganese ion contrasted T(1)-weighted magnetic resonance imaging in rats.
To examine the usefulness of Mn(2+) contrasted magnetic resonance imaging (MRI) in hypothalamic imaging, images obtained using T(1)-weighted MRI were compared with Fos expression, which is known to increase after activation of voltage-dependent Ca(2+) channels. Intravenous infusion of MnCl(2) elicited a rapid increase in the T(1)-weighted MRI signal intensity in the vessels and ventricles, but not in the brain parenchyma, suggesting that Mn(2+) did not diffuse freely across the blood-brain barrier. When the blood-brain barrier was broken by right intracarotid arterial injection of 25% D-mannitol, an increased signal intensity was seen in the right brain. Intracarotid arterial injection of hypertonic NaCl elicited rapid and striking increases in signal intensity in the paraventricular hypothalamic nucleus, supraoptic nucleus, and preoptic area, which are thought to be involved in central osmotic regulation. These observations were consistent with the Fos expression results. These results indicate that Mn(2+) contrasted MRI is a useful technique for investigating the autonomic center in the hypothalamus.
Morita
Hironobu
H
Department of Physiology, Gifu University School of Medicine, 40 Tsukasa-Machi, Gifu 500-8705, Japan. morita@cc.gifu-u.ac.jp
Ogino
Takashi
T
Seo
Yoshiteru
Y
Fujiki
Nobuhiro
N
Tanaka
Kunihiko
K
Takamata
Akira
A
Nakamura
Shun
S
Murakami
Masataka
M
D000818:Animals; D001812:Blood-Brain Barrier; D002339:Carotid Arteries; D003287:Contrast Media; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology*; D007150:Immunohistochemistry; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D007477:Ions; D015636:Magnesium Chloride / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D008297:Male; D008345:Manganese / Q000493:pharmacokinetics; D008353:Mannitol / Q000494:pharmacology; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology; D011301:Preoptic Area / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D013495:Supraoptic Nucleus / Q000502:physiology
D003287:Contrast Media; D007477:Ions; D016760:Proto-Oncogene Proteins c-fos; D012462:Saline Solution, Hypertonic; D015636:Magnesium Chloride; D008353:Mannitol; D008345:Manganese