Modulation by food restriction of intracellular calcium signaling in parotid acinar cells of aging Fischer 344 rats.
Previous studies suggest that alpha 1-adrenergic (alpha 1-AR)-induced intracellular calcium ([Ca2+]i) mobilization in rat parotid acinar cells declines with age. In this study, we examined the effects of food restriction on alpha 1-AR and muscarinic-stimulated [Ca2+]i mobilization in parotid acinar cells during aging. [Ca2+]i levels in response to the alpha 1-AR agonist epinephrine and the muscarinic agonist carbachol were evaluated in Fura-2-loaded parotid acinar cells from ad libitum-fed (AL) and food-restricted (FR) Fischer 344 male rats at 4, 6, 14, and 24 months of age. [Ca2+]i responses to epinephrine and carbachol (10 microM) were significantly reduced (48% and 35%, respectively; p < .05) in cells from 24-month-old AL rats as compared to younger AL rats. In contrast, no significant reduction of epinephrine and carbachol responses was observed in 24-month-old FR animals. An age-related increase in basal [Ca2+]i (peak around 14 months; p < .02) was observed in both AL and FR rats. In addition, basal [Ca2+]i was higher in FR than in AL rats at 14 and 24 months of age (p < .02). These studies suggest that FR partially attenuates or delays age-related impairments in alpha 1-AR- and muscarinic-cholinergic signal transduction systems of parotid acinar cells. Basal [Ca2+]i also appears to be altered during aging and by FR.
Olsen
J G
JG
Department of Medicine, University of Texas Health Science Center at San Antonio, USA.
Salih
M A
MA
Harrison
J L
JL
Herrera
I
I
Luther
M F
MF
Kalu
D N
DN
Lifschitz
M D
MD
Katz
M S
MS
Yeh
C K
CK
D000322:Adrenergic Agonists / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005508:Food Deprivation; D007425:Intracellular Membranes / Q000378:metabolism*; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction
D000322:Adrenergic Agonists; D018721:Muscarinic Agonists; D002118:Calcium