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Biomedical subjects

J W Ternes

Publications and source records attributed to J W Ternes.

18 recordsLinked to original sources
PubMed1990

The opioids: abuse liability and treatments for dependence.

The opioids vary greatly in addictive potential, from the highly addictive such as heroin to the opioid antagonists such as naltrexone, which can be used to treat opioid dependence and overdose. The various opioid compounds have different euphorigenic properties and also produce withdrawal syndromes of distinct patterns of duration and intensity. Dependence liability is affected by both the pleasure-seeking motives for initiating drug use and the painful consequences of abstinence or withdrawal. Detoxification, which takes 7-10 days for the short-acting opioids, is usually the first stage in treatment. Methadone is often used as a preliminary stage in detoxification, but some patients are maintained on methadone for years, since it allows them to lead relatively normal lives. Non-opioid drugs used to control withdrawal symptoms include clonidine. After detoxification, naltrexone, a long-acting opioid antagonist, can be administered orally to prevent relapse.

Humans↗
PubMed1986

Opiate receptors, neuropeptides in CNS and CSF of two Macaca species with different responsiveness to opiates.

Of two related Macaca species, the rhesus (M. mulatta), acquires opiate tolerance and dependence more readily than the cynomolgus (M. fascicularis). In the cynomolgus, mu-opiate receptors were significantly fewer in the caudate nucleus and globus pallidus; delta-sites were fewer in the thalamus. kappa-Sites showed no species difference. The levels of [Met5]enkephalin, substance P and dynorphin B in various brain areas were comparable. On the other hand, receptor-assayed endorphin activity was higher in CSF of cynomolgus than rhesus monkeys.

Animals↗
PubMed1985

Rats learn to like the taste of morphine.

When rats are forced to drink a morphine solution as their only source of fluid, they eventually reverse their initial preference and drink more morphine than water in a two-bottle preference test. The cause of this shift in preference was examined with the taste reactivity test which involves the analysis of fixed action patterns elicited by taste solutions infused into rats' mouths. Three morphine concentrations and two levels of motivation were studied. A greater percentage of ingestive taste reactivity responses occurred to the oral morphine infusion in morphine-raised rats than in water-raised rats. These data argue against the idea that enhanced morphine ingestion is caused by anticipation of positive consequences. Instead, they support the idea that rats come to "like" the flavor of the morphine solution; in other words, the palatability evaluation of the morphine changes, possibly through an association between the flavor and the hedonically positive effects of the morphine.

Animals↗
PubMed1985

Nondependent monkeys self-administer hydromorphone.

Four monkeys, 2 rhesus and 2 cynomolgus, were trained to perform a multiple fixed-ratio extinction (MULT/FR/EXT) schedule for banana pellets. Subsequently, all animals were given hydromorphone (HYM) self-administration training, which consisted of substitution of FR (fixed ratio) 2 cocaine for FR 80 banana pellets and substitution of FR 2 HYM for FR 2 cocaine. All of the animals acquired cocaine self-administration. They also acquired HYM self-administration when it was substituted for cocaine. Next, 50 HYM self-maintenance sessions were given. During these sessions, animals were allowed to self-administer a total cumulative dose of 1 mg/kg/day of HYM. The animals were observed for spontaneous withdrawal while they performed an operant for food 24 and 48 hr after their last maintenance dose of HYM. Because none of the monkeys showed signs of spontaneous withdrawal or disruption of the appetitive baseline during the first postmaintenance appetitive session, a 0.4-mg dose of naloxone was administered noncontingently to test for precipitated withdrawal. Naloxone disrupted appetitive responding for banana pellets in the 2 rhesus monkeys. Naloxone had no effect on responding for food in the cynomolgus monkeys. Because none of the monkeys showed signs of spontaneous withdrawal or disruption of their appetitive baseline during the second postmaintenance session, a HYM challenge dose of 1 mg/kg was given noncontingently to assess whether tolerance to the daily maintenance dose had been acquired. The bolus dose of HYM suppressed lever pressing for food in both species, a result indicating a lack of tolerance. These results suggest that the positive reinforcing properties of HYM are sufficient to maintain opioid self-administration and that tolerance and physical dependence are not necessary.

Animals↗
PubMed1984

Salt hunger in the rhesus monkey.

Five rhesus monkeys (Macaca mulatta) were placed on a low-sodium diet and given injections of furosemide in order to promote sodium loss. The results indicated that these methods elicit a substantial and specific salt hunger. Issues surrounding salt hunger are discussed.

Animals↗
PubMed1983

Cynomolgus monkeys do not develop tolerance to opioids.

In order to examine the development of tolerance to opioids, eight cynomolgus and two rhesus monkeys were trained to press a lever for food reinforcement and then were catheterized so that drugs could be infused. Three doses of hydromorphone and six different interdose intervals were studied. Hydromorphone infusions initially suppressed lever pressing for food in both species. The rhesus monkeys acquired tolerance to these sedative effects after 14 exposures to the opioid. However, the cynomolgus monkeys failed to acquire tolerance after more than 100 exposures. Naloxone challenge elicited withdrawal symptoms from the rhesus monkeys but not from the cynomolgus monkeys. This differential response to sustained opioid administration in these closely related species suggests that a genetic mechanism may underlie tolerance to and physical dependence on opioids.

Animals↗
PubMed1982

Absence of naloxone sensitivity in obese humans.

Studies in rodents suggest the possibility of an association between elevated endogenous opiate activity and overeating and obesity. One measure of elevated opiate activity is sensitivity to the opiate antagonist naloxone. Seven massively obese human subjects showed no subjective or physiological sensitivity to large intravenous doses of naloxone. This finding fails to support a relationship between elevated endorphin activity and human obesity.

Arousal↗
PubMed1981

An electrodermal measure of arousal in opiate addicts to drug-related stimuli.

Frequency per minute of spontaneous skin resistance responses (SSRRs), an inferred measure of arousal, was compared for three groups of subjects when exposed to drug-related and neutral stimuli. The three groups were a recently detoxified opiate addict group, a group maintained on methadone, and a non-addict control group. Stimuli consisted of slides, objects, and video-tapes, all showing either items used in drug-preparation for self-injection, or neutral items. Results showed clear evidence of an increase in rate of response to drug-related cues in the detoxified drug-free group as compared to the other two groups. No differences were found in response to the neutral stimuli. It is concluded that the present finding of increased arousal to drug-related cues in recently detoxified patients may be an important component of withdrawal, which in turn is regarded as a conditioned autonomic response leading to instrumental behavior of readdiction.

Adult↗