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Biomedical subjects

T E Hunt

Publications and source records attributed to T E Hunt.

16 recordsLinked to original sources

The effects of serotonin biosynthesis inhibition on nicotine and nifedipine-induced analgesia in rats.

UNLABELLED: The calcium channel blocker nifedipine has analgesic properties that are enhanced by nicotine. Although it is not known how this analgesic state might affect the awareness of anginal pain and impending myocardial infraction, recent studies have shown an increased mortality associated with the use of large doses of nifedipine. Because both nifedipine- and nicotine-induced analgesia involve serotonergic mechanisms, we studied the effects of the serotonin biosynthesis inhibitor parachlorophenylalanine (pCPA) on nifedipine- and nicotine-induced analgesia. Nociception was assessed by tail-flick method. Rats pretreated with pCPA (300 mg/kg intraperitoneally [IP]) followed by either nifedipine (15 mg/kg IP) or nicotine (1 mg/kg subcutaneously) had a increase in tail-flick latency of 41% (P = 0.09) and 50% (P = 0.05), respectively, compared with animals that did not receive pCPA. Additionally, rats pretreated with pCPA followed by a combination of nicotine and nifedipine doubled their tail-flick latency (P = 0.0001) compared with animals that were not treated with pCPA. These data further support the involvement of the serotonergic system in both nifedipine- and nicotine-induced analgesia and suggest that drugs that affect serotonin levels, including tricyclic antidepressants and serotonin-specific reuptake inhibitors, may also affect the analgesia induced by nifedipine and nicotine. IMPLICATIONS: This study examines the effect of serotonin depletion on nicotine- and nifedipine-induced analgesia. Nifidipine is a calcium channel blocker used to treat high blood pressure. It also has pain-relieving properties that are enhanced by nicotine. Because both nifedipine- and nicotine-induced analgesia involve the neurotransmitter serotonin, it is important to know how changes in serotonin concentration might affect both nicotine- and nifedipine-induced analgesia. This study not only supports the involvement of the serotonergic system in both nifidipine- and nicotine-induced analgesia, but also suggests that drugs that affect serotonin levels may also affect analgesia induced by nifidipine and nicotine.

Analgesics, Non-Narcotic↗

Ondansetron exhibits the properties of a local anesthetic.

UNLABELLED: The purpose of this study was to determine whether ondansetron (OND) has local anesthetic effects. Using a patch-clamp technique, we showed that OND concentration dependently blocked Na channel currents in freshly isolated neurons of rat brains with a 50% inhibition concentration of 12 microM. The blockade started immediately when OND was applied to the cell body using a fast perfusion system, reached a plateau within 15 s, and recovered to the control level within 30 s after washout of the OND-containing solution. Because this is a known property of local anesthetics, we used the tail-flick technique to verify this effect in vivo in Sprague-Dawley rats (n = 46). OND was injected subcutaneously into the tail at the doses of 0.08, 0.16, and 0.2 mg. The tail-flick latency increased 2 min after OND injection, reaching the plateau within 5 min. This effect was dose-related, lasting from 10 to 25 min. These preliminary data indicate that OND, a selective 5-HT3 receptor antagonist, might serve as a prototype molecule for development of a novel series of local anesthetics. IMPLICATIONS: Ondansetron is a drug used to prevent vomiting, especially in cancer patients after chemotherapy. We found that it also causes numbness when injected under the skin. This new action may contribute to its role in "calming the stomach." We studied the effect of ondansetron on the isolated brain cells of live rats.

Anesthetics, Local↗

Ondansetron blocks nifedipine-induced analgesia in rats.

The serotonergic system is involved in pain transmission and the 5-hydroxytryptamine (5-HT3) receptor subtype mediates some of these effects at the spinal level. Therefore, we explored the effects of the serotonergic system on nifedipine-induced analgesia by using the 5-HT3 receptor antagonist ondansetron. Male Sprague-Dawley rats were pretreated with ondansetron (1 mg/ kg intraperitoneally) or normal saline. After 15 min, rats received injections of nifedipine (15 mg/kg intraperitoneally) or dimethylsulfoxide (DMSO), solvent for nifedipine, as a control. Nociception was assessed by tail-flick method. Rats treated with nifedipine alone had an increase in tail-flick latency of 122%, as measured by the area under the curve, compared to rats treated with DMSO alone. Pretreatment with ondansetron, however completely blocked the analgesic effect of nifedipine, with tail-flick latency remaining at baseline throughout the measurement period. These results indicate that the 5-HT3 receptor plays an important role in the analgesic response to nifedipine and that medications that block this receptor may decrease the analgesic effectiveness of this type of therapy.

Analgesia↗

Practical considerations in the rehabilitation of the aged.

Enlightened geriatric care provides assistance to the elderly for living independently as long as possible. Essential to this amenity is the high priority placed upon restoration in coordination with other forms of therapy. Medical rehabilitation too often has been associated with employment-oriented goals and with major physical achievements. Restoration of the young spinal-injured paraplegic patient has been a model for rehabilitation medicine. The aged, also, often can be restored to optimal levels of functional capacity commensurate with their lesser needs. Rehabilitative principles for the management of disability are the same in old age as at any other time of life. Certain age-related factors, however, profoundly influence programs of restoration for the elderly. These factors need full consideration when physicians plan appropriate care for their aged patients. A list of guidelines is presented.

Aged↗

One third of a million days of care at home, 1959 to 1975.

Although articles on studies of organized home care programs are numerous, reports of long-term effectiveness of these programs are scanty. While government spokesmen appear to advocate more widespread use of alternatives to hospitalization, there has been serious criticism of the efficiency and accomplishments of home care services. A medically oriented home care program in Saskatoon (population, less than 150 000) has grown steadily over a 16-year period and is now serving a daily average of 200 individuals. All patients have required "hospital-like care" at home and most have not ordinarily been sufficiently mobile during their time in the program to attend hospital outpatient services. Many have required "concentrated care" through daily visits of professional health personnel. The program is designed for the physically ill and disabled and is administered by the major teaching hospital in the city, although it provides services to the whole community. Over one third of the patients referred in recent years had been at home. Almost one half of the patients have undergone satisfactory rehabilitation at home. The program has also proven to be an acceptable alternative to long-term institutional care for the permanently seriously disabled, a large number of whom are elderly. The program has been able to operate at considerably less cost to the public than inpatient (hospital or institutional) services would have entailed.

Consumer Behavior↗

Management of chronic non-rheumatic pain in the elderly.

Chronic non-rheumatic pain in the aged should be viewed in the context of physiologic and clinical alterations due to aging which may create diagnostic problems. In the elderly, the abnormality of the clinical presentation and the patient's failure to remember the time and the nature of the precipitating incident may be extremely misleading. Many clinical features may also be altered by the aging process itself. Thus the unwary physician is apt to be mistaken in establishing the etiologic basis for pain syndromes. Once a diagnosis has been achieved, it should be evaluated in the light of other age-related disturbances. Treatment should be as simple as possible. The prescription of combination preparations may involve use of a drug that is beneficial for one disorder but harmful for another. Aged persons display a marked tendency toward abnormal reactions to the usual drug regimens. A wise combination of treatment by medical means (including drugs), physiotherapy, and sometimes surgical procedures, usually is effective for the relief of this type of chronic pain.

Aged↗