Adrenoceptor coupling mechanisms which regulate salivary secretion during aging.
In parotid slices and membranes from Wistar rats 2, 12 and 24 months old, changes are noted in adrenoceptor-stimulated K+ fluxes, formation of [3H]inositol phosphates ([3H]IPs), cAMP production, and membrane environment. Norepinephrine-stimulated K+ efflux and formation of [3H]IPs in the slices proceed through an alpha 1-adrenergic mechanism and are reduced 20% and 40% during aging, respectively. In beta-adrenoceptor stimulation with isoproterenol, no age changes were observed in K+ influx and cAMP production. The cholesterol content in membranes was reduced with age; concomitantly, the membrane viscosity decreased with age. These results indicate that the alterations in the membrane environment may provide age-dependent modulation of alpha 1-adrenoceptor coupling mechanisms and their functions.
Miyamoto
A
A
Department of Pharmacology, School of Medicine, Sapporo Medical University, Japan.
Araiso
T
T
Koyama
T
T
Ohshika
H
H
D000375:Aging / Q000502:physiology*; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology*; D010306:Parotid Gland / Q000254:growth & development / Q000502:physiology*; D010743:Phospholipids / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*; D012463:Saliva / Q000378:metabolism*; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D014783:Viscosity
D007295:Inositol Phosphates; D010743:Phospholipids; D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta; D012471:Salivary Proteins and Peptides; D000242:Cyclic AMP; D007545:Isoproterenol; D011188:Potassium; D009638:Norepinephrine