Alterations of muscarinic cholinergic receptors in the hippocampal formation of stressed rat: in vitro quantitative autoradiographic analysis.
Alterations in muscarinic cholinergic (mACh) binding sites in the hippocampal formation of rats after immobilization stress (IM-stress) lasting 0.5 or 3 h were quantitated using a computer-assisted image analysis system on autoradiograms following labeling of frozen sections with [3H]quinuclidinyl benzilate (QNB). The concentration of acetylcholine (ACh) in the rat hippocampus after IM-stress was also measured and showed no significant change compared to control. IM-stress for 0.5 h produced significant increases in the concentration of mACh binding sites in the whole hippocampal formation and in two subdivisions studied (CA1 plus CA2 and dentate gyrus); after 3 h of stress, the increase remained significant only in the dentate gyrus. These findings suggest that IM-stress induce a hypersensitivity of the septo-hippocampal cholinergic system and the 'up-regulation' of postsynaptic mACh receptors is more lasting in the dentate gyrus than in the hippocampus as a whole.
Mizukawa
K
K
Department of Anatomy, Okayama University Medical School, Japan.
Takayama
H
H
Sato
H
H
Ota
Z
Z
Haba
K
K
Ogawa
N
N
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D002799:Cholinergic Fibers / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D000109:Acetylcholine