TY - JOUR
T1 - Aging affects isoproterenol-induced water drinking, astrocyte density, and central neuronal activation in female Brown Norway rats
AU - Hardy, Rachel N.
AU - Simsek, Zinar D.
AU - Curry, Brandon
AU - Core, Sheri L.
AU - Beltz, Terry
AU - Xue, Baojian
AU - Johnson, Alan K.
AU - Thunhorst, Robert L.
AU - Curtis, Kathleen
N1 - Funding Information:
These studies were supported by Oklahoma Center for the Advancement of Science and Technology (OCAST) Health Research Program 12-196 (KSC), OK INBRE Program 8P20GM103447 (ZS, BC), AG25465 (RLT) and HL098207 , MH80241 and HL14388 (AKJ).
Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/8/1
Y1 - 2018/8/1
N2 - Age-dependent impairments in the central control of compensatory responses to body fluid challenges have received scant experimental attention, especially in females. In the present study, we found that water drinking in response to β-adrenergic activation with isoproterenol (30 μg/kg, s.c.) was reduced by more than half in aged (25 mo) vs. young (5 mo) ovariectomized female Brown Norway rats. To determine whether this age-related decrease in water intake was accompanied by changes in central nervous system areas associated with fluid balance, we assessed astrocyte density and neuronal activation in the SFO, OVLT, SON, AP and NTS of these rats using immunohistochemical labeling for GFAP and c-fos, respectively. GFAP labeling intensity was increased in the SFO, AP, and NTS of aged females independent of treatment, and was increased in the OVLT of isoproterenol-treated rats independent of age. Fos immunolabeling in response to isoproterenol was reduced in both the SFO and the OVLT of aged females compared to young females, but was increased in the SON of female rats of both ages. Finally, fos labeling in the AP and caudal NTS of aged rats was elevated after vehicle control treatment and did not increase in response to isoproterenol as it did in young females. Thus, age-related declines in water drinking are accompanied by site-specific, age-related changes in astrocyte density and neuronal activation. We suggest that astrocyte density may alter the detection and/or processing of signals related to isoproterenol treatment, and thereby alter neuronal activation in areas associated with fluid balance.
AB - Age-dependent impairments in the central control of compensatory responses to body fluid challenges have received scant experimental attention, especially in females. In the present study, we found that water drinking in response to β-adrenergic activation with isoproterenol (30 μg/kg, s.c.) was reduced by more than half in aged (25 mo) vs. young (5 mo) ovariectomized female Brown Norway rats. To determine whether this age-related decrease in water intake was accompanied by changes in central nervous system areas associated with fluid balance, we assessed astrocyte density and neuronal activation in the SFO, OVLT, SON, AP and NTS of these rats using immunohistochemical labeling for GFAP and c-fos, respectively. GFAP labeling intensity was increased in the SFO, AP, and NTS of aged females independent of treatment, and was increased in the OVLT of isoproterenol-treated rats independent of age. Fos immunolabeling in response to isoproterenol was reduced in both the SFO and the OVLT of aged females compared to young females, but was increased in the SON of female rats of both ages. Finally, fos labeling in the AP and caudal NTS of aged rats was elevated after vehicle control treatment and did not increase in response to isoproterenol as it did in young females. Thus, age-related declines in water drinking are accompanied by site-specific, age-related changes in astrocyte density and neuronal activation. We suggest that astrocyte density may alter the detection and/or processing of signals related to isoproterenol treatment, and thereby alter neuronal activation in areas associated with fluid balance.
KW - Area postrema
KW - Nucleus of the solitary tract
KW - Organum vasculosum of the lamina terminalis
KW - Subfornical organ
KW - Supraoptic nucleus
UR - http://www.scopus.com/inward/record.url?scp=85043339459&partnerID=8YFLogxK
U2 - 10.1016/j.physbeh.2018.03.005
DO - 10.1016/j.physbeh.2018.03.005
M3 - Article
C2 - 29518407
AN - SCOPUS:85043339459
SN - 0031-9384
VL - 192
SP - 90
EP - 97
JO - Physiology and Behavior
JF - Physiology and Behavior
ER -