TY - JOUR
T1 - Age-related changes in brain catecholamine responses to a single footshock
AU - Welsh, K. A.
AU - Gold, P. E.
N1 - Funding Information:
The present experiment attempts to assess further the functional integrity of the aged central adrenergic systems by examining their responses to brief acute footshock. There were two major reasons for our interest in the responses to a brief footshock of modest intensity. First, this footshock has been demonstrated to be sufficient to elicit a transient decrease in brain (NE) concentrations in young adult (90-day) rats. The decrease is maximal at 10 min after footshock and NE concentrations return to baseline over the next 30-90 minutes \[7, 1 I, 12\]. The transient decrease after an acute footshock is seen in most brain areas and is accompanied by an increase in MHPG levels \[35\].T ransient central noradrenergic decreases such as these, particularly when seen with concomitant MHPG increases, most likely reflect release of the amine followed by a homeostatic return to baseline levels \[30\]. Second, footshock such as that employed here is commonly used by our laboratory \[8\] and others \[18,37\] in avoidance training procedures to assess memory functions in aged rats. Because posttraining changes in central norepinephrine levels are tightly related to ~Supported by the National Institutes on Aging (AG 01642) and Mental Health (MH 31141) and by an award from the James McKeen Cattell Foundation. 2To whom requests for reprints should be addressed.
PY - 1984
Y1 - 1984
N2 - -The responses of forebrain and brainstem catecholamine levels to a single footshock were studied in 70-day, one-year, and two-year-old Fischer-344 rats. Brain catecholamine concentrations were assessed 10 minutes after a single 2 second footshock (0, 0.3, or 2.0 mA). In samples taken from non-footshocked rats, only forebrain dopamine concentrations showed a significant age-related decline. However, because the net weights of both the forebrain and the brainstem samples increased significantly with age, the content of forebrain dopamine did not exhibit a significant decline. Both norepinephrine and dopamine levels showed age-related changes in responsiveness to footshock. Norepinephrine concentrations were reduced in both the forebrain and brainstem samples obtained 10 minutes after the high footshock in both the 70-day and one-year-old animals. In two-year-old rats, however, neither forebrain nor brainstem norepinephrine concentrations were altered in response to footshock. Seventy-day-old rats demonstrated significant footshock-induced increases in brainstem dopamine levels, one-year olds showed no appreciable change, and two-year olds demonstrated a non-significant footshock-induced decrease. Thus, both noradrenergic and dopaminergic systems demonstrated age-related changes in their responsiveness to a single brief footshock. These alterations may contribute to the declining ability of the senescent animals to adapt to stressful situations.
AB - -The responses of forebrain and brainstem catecholamine levels to a single footshock were studied in 70-day, one-year, and two-year-old Fischer-344 rats. Brain catecholamine concentrations were assessed 10 minutes after a single 2 second footshock (0, 0.3, or 2.0 mA). In samples taken from non-footshocked rats, only forebrain dopamine concentrations showed a significant age-related decline. However, because the net weights of both the forebrain and the brainstem samples increased significantly with age, the content of forebrain dopamine did not exhibit a significant decline. Both norepinephrine and dopamine levels showed age-related changes in responsiveness to footshock. Norepinephrine concentrations were reduced in both the forebrain and brainstem samples obtained 10 minutes after the high footshock in both the 70-day and one-year-old animals. In two-year-old rats, however, neither forebrain nor brainstem norepinephrine concentrations were altered in response to footshock. Seventy-day-old rats demonstrated significant footshock-induced increases in brainstem dopamine levels, one-year olds showed no appreciable change, and two-year olds demonstrated a non-significant footshock-induced decrease. Thus, both noradrenergic and dopaminergic systems demonstrated age-related changes in their responsiveness to a single brief footshock. These alterations may contribute to the declining ability of the senescent animals to adapt to stressful situations.
KW - Catecholamines
KW - Dopamine
KW - Epinephrine
KW - Norepinephrine
KW - Stress
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U2 - 10.1016/0197-4580(84)90086-1
DO - 10.1016/0197-4580(84)90086-1
M3 - Article
C2 - 6738786
AN - SCOPUS:0021173848
SN - 0197-4580
VL - 5
SP - 55
EP - 59
JO - Neurobiology of Aging
JF - Neurobiology of Aging
IS - 1
ER -