Hippocampal Gαq/11 but not Gαo-coupled receptors are altered in aging

► This study uses a naturally occurring model of cognitive aging in the rat. ► Basal GTPγS-binding to Gαq/11 is elevated in the aged hippocampus. ► Muscarinic stimulation of [Ca2+]i is blunted in aged hippocampus. ► GPCR stimulation of [Ca2+]i is more dependent on ICS in aged hippocampus. ► These effects of age are not related to spatial learning impairment.