In vivo adaptative regulation of muscarinic receptors and muscarinic stimulation-induced Ca2+ mobilization during short-term heat exposure in rat parotid glands.
1. Adaptation of muscarinic receptors (MR)--muscarinic stimulation--induced intracellular Ca2+ mobilization during short-heat exposure (33 degrees C). 2. Heat-exposure for 48 hr decreased the carbachol (CCh)-stimulated cytosolic Ca2+ concentration increase. 3. The number of MR on cell surface increased transiently at 24 hr with a subsequent decrease at 48 hr. 4. CCh-stimulated inositol triphosphate (IP3) formation decreased at 48 hr. 5. In saponin-permeabilized cells, 1,4,5-IP3-induced 45Ca2+ release decreased at 24 hr. 6. The data suggest that the adaptation for increased muscarinic stimulation occurs at IP3 generating sites as well as at intracellular IP3 receptor sites during heat exposure.
Fujinami
H
H
Department of Pharmacology, Tokyo College of Pharmacy, Japan.
Komabayashi
K
K
Izawa
T
T
Suda
K
K
Tsuboi
M
M
D000109:Acetylcholine / Q000378:metabolism; D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D015536:Down-Regulation / Q000502:physiology; D006358:Hot Temperature; D007293:Inosine Triphosphate / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D019832:N-Methylscopolamine; D018377:Neurotransmitter Agents / Q000378:metabolism; D010276:Parasympatholytics / Q000378:metabolism; D010277:Parasympathomimetics / Q000494:pharmacology*; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012602:Scopolamine Derivatives / Q000378:metabolism
D002132:Calcium Radioisotopes; D007295:Inositol Phosphates; D018377:Neurotransmitter Agents; D010276:Parasympatholytics; D010277:Parasympathomimetics; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D007293:Inosine Triphosphate; D000109:Acetylcholine; D002118:Calcium; D019832:N-Methylscopolamine