Article Abstract:
Arginine vasopressin (AVP) is a hormone that causes blood vessels to constrict and blood pressure to rise. AVP is released in response to nervous stimulation when a person changes posture, or the osmolality of the blood changes, or by a number of different mechanisms that stimulate nervous activity in the baroreflex pathway. Recent studies have shown that aging increases AVP release when osmotic stimuli are operating, but that aging decreases AVP response in relation to stimuli produced by postural changes. Metoclopramide (MCP), a drug that directly affects the baroreflex pathway, has also been found to stimulate AVP secretion in elderly subjects. This study examined whether such increases in AVP secretion also occurred in response to smoking and to insulin-induced hypoglycemia (low blood sugar). Thirty men, all heavy smokers, were examined for AVP secretion in response to MCP, smoking, and insulin-induced hypoglycemia. The men were separated into three groups based upon age: 22 to 39 years, 42 to 60 years, and 63 to 81 years. Basal AVP levels were similar for all three groups. AVP response to MCP was significantly greater in the oldest group than in the younger groups, with a peak AVP 2.5 times that of the basal level. Smoking increased AVP levels in all three groups, with increases to 2.5 times basal levels in the two younger groups and 3.25 times basal in the oldest group. The responses to insulin were similar in all three groups. These results show that AVP release increases with age in response to some stimuli, but not others. This suggests that aging causes changes that result in some signals being distorted, which affects the cells that produce AVP; thus some pathways are affected by aging, but others are not. (Consumer Summary produced by Reliance Medical Information, Inc.)
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
Neuroleptic medications are used to treat psychotic disorders and in the elderly, to control agitation and sometimes nausea. One side effect of this class of drugs is a motion disorder known as tardive dyskinesia (TD). A symptom of TD is decreased hand force steadiness, but this can also occur with advanced age. Whether there is greater impairment of hand force steadiness in older patients treated with neuroleptics was the subject of the present study. Subjects were 40 patients ranging in age from 23 to 80 years old who were being treated with neuroleptics but showed no evidence of TD, and 43 age-matched controls who were not being treated. The subjects' ability to maintain steady force with their fingers was tested for 30 seconds. Results highlighted a main effect of age by group, such that patients over the age of 45 had significantly greater force instability than patients under the age of 45. Controls over the age of 45 did not differ from younger controls; exposure to neuroleptics increased force instability in the older age group only. Support is therefore lent to the hypothesis that aging psychiatric patients are increasingly sensitive to neuroleptic medications. Advanced age is the most important risk factor for the development of neuroleptic-induced TD. (Consumer Summary produced by Reliance Medical Information, Inc.)
User Contributions:
Comment about this article or add new information about this topic:
Article Abstract:
The synthesis of two members of the heat shock protein (HSP) 70 family, hsc70 and hsp70, before and after mild heat shock is assessed. Hepatocytes isolated from young adult and old rats did not synthesize detectable amounts of hsp70 after incubation at 37 degrees centigrade. On the other hand, incubation at 42.5 degrees centigrade for 30 minutes induced the synthesis of hsp70 and hsc70. Hepatocytes from old rats had lower rates of hsp70 synthesis than the young adult rats. Synthesis of hsc70 did not change between the two rat groups. Thus, rat hepatocytes have decreased ability to synthsize hsp70 with aging.
User Contributions:
Comment about this article or add new information about this topic: