Effects of age, postmortem delay and storage time on receptor-mediated activation of G-proteins in human brain.
The influence of age, postmortem delay and freezing storage period on receptor-mediated G-protein activity was quantified in cortical membranes from 34 healthy subjects. Concentration-response curves of the [(35)S]GTPgammaS binding stimulation by agonists for alpha(2)-adrenoceptors (UK14304), mu-opioid (DAMGO), 5-HT(1A) (8-OH-DPAT), GABA(B) (baclofen) and muscarinic (carbachol) receptors were analyzed. Immunoreactivities of G(alpha)-protein subunits were also determined. Basal binding and UK14304, 8-OH-DPAT, and baclofen potency to stimulate [(35)S]GTPgammaS binding decreased with aging (1-88 years) without changes of efficacy. DAMGO-mediated stimulation increased both in potency and efficacy with aging. A negative correlation between age and immunoreactivity was observed for G(alphai1/2)-, but not for G(alphai3)-, G(alphao)-,and G(alphas)-proteins. Neither [(35)S]GTPgammaS binding nor G(alpha)-proteins changed with the postmortem delay (8-92 h). Basal [(35)S]GTPgammaS binding decreased with the sample storage period (1-85 months). A careful match between cases and controls should be taken into account when designing signal transduction studies in human disorders, specially for variables such as age and storage period.
González-Maeso
Javier
J
Department of Pharmacology, University of the Basque Country, E-48940 Leioa, Bizkaia, Spain.
Torre
Iratxe
I
Rodríguez-Puertas
Rafael
R
García-Sevilla
Jesús A
JA
Guimón
José
J
Meana
J Javier
JJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D001921:Brain / Q000473:pathology; D001923:Brain Chemistry / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D015925:Cryopreservation; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000819:agonists / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007223:Infant; D008566:Membranes / Q000737:chemistry; D008875:Middle Aged; D011180:Postmortem Changes; D013997:Time Factors; D014021:Tissue Preservation
D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins