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Biomedical subjects

L B Wallnau

Publications and source records attributed to L B Wallnau.

12 recordsLinked to original sources
PubMed1983

Opiate effects on isolation-induced hyperthermia.

The effect of brief separation from companions on temperature was studied in 24-day-old chickens. It was found that socially isolated animals became hyperthermic. Alternatively, control animals maintained in groups larger than 6 animals displayed no differences in temperature between the pre- and post-test. Injections of naloxone produced dose-dependent temperature increases in socially housed animals. Finally, while morphine reversed isolation hyperthermia, it had little or no effect on temperature in animals that remained in social groups throughout the experiment. The findings are discussed in terms of endogenous opioid involvement in separation distress and social bonding.

Animals↗
PubMed1981

The effects of quipazine, fenfluramine and apomorphine on the morphine potentiation of tonic immobility.

Acute administration of morphine (2 mg/kg, IM) enhanced tonic immobility (TI) durations in three-week old chickens. This effect could be reversed with the 5-HT receptor agonist quipazine. Similarly, promoting 5-HT release by fenfluramine antagonized the morphine potentiation of the response. Both 5-HT agonists reduced TI durations. Finally, the DA receptor agonist apomorphine produced decrements in TI duration and blocked the effect of morphine. The results suggest the involvement of serotonergic and dopaminergic mechanism in the morphine potentiation of the response. The findings are also discussed in terms of a revised serotonergic model of tonic immobility.

Animals↗
PubMed1981

The effects of tryptophan and manipulations of serotonergic receptors on tonic immobility in chickens.

The effects of serotonergic manipulations on tonic immobility (TI) were examined. Systemic injections of tryptophan enhanced TI duration. This effect was reversed by quipazine, a 5-HT receptor agonist, and p-chloroamphetamine, a 5-HT releaser. Separately, these drugs caused marked reductions in TI duration. Fenfluramine, which promotes 5-HT release, also reduced TI duration. The quipazine attenuation of TI was prevented by pretreatment with the 5-HT receptor blocker cinanserin. The results are discussed in terms of 5-HT receptor mechanisms and the raphe model of tonic immobility.

Animals↗
PubMed1981

Tonic immobility in domestic fowl: possible interaction of serotonergic and dopaminergic mechanisms.

Treatment with the dopamine (DA) receptor blocker, haloperidol, enhanced tonic immobility (TI) duration. Fenfluramine, a receptor agonist for serotonin (5-HT), reversed this effect. Tryptophan produced long TI reactions, and is believed to do so due to impaired synaptic transmission of 5-HT following its direct inhibitory effects on 5-HT neurons. DA receptor stimulation by apomorphine prevented the tryptophan potentiation of tonic immobility. The results suggest that serotonergic and dopaminergic systems may interact with respect to tonic immobility.

Animals↗
PubMed1980

Tonic immobility in domestic fowl: anticataleptic effects of quipazine.

Quipazine, a putative serotonergic agonist, produced marked decreases in tonic immobility (TI) duration in doses of 5--25 mg/kg. Quipazine-treated animals required more elicitation attempts before displaying TI. Quipazine also blocked the haloperidol enhancement of tonic immobility. In a third experiment, quipazine produced stereotyped responses in chickens which yielded increases in activity on a stabilimeter platform. The results are discussed in terms of catalepsy and serotonerigic and dopaminergic mechanisms.

Animals↗
PubMed1980

Failure to find self-recognition in mother-infant and infant-infant rhesus monkey pairs.

To date, chimpanzees, orangutans, and humans are the only species which have been shown capable of recognizing themselves in mirrors. In an attempt to make the identity of the reflection more explicit we report two experiments in which rhesus monkeys were given paired access to a common mirror over an extended period. While developmental differences in mirror behavior were obtained, signs of self-recognition failed to emerge. The results were discussed in terms of the absence in monkeys of an essential cognitive category for processing mirrored information about the self.

Animals↗
PubMed1979

Tonic immobility: effects of dopamine receptor blockade and stimulation.

Blockade of dopaminergic receptors by haloperidol enhanced the duration of tonic immobility in chickens. Apomorphine, a dopamine receptor agonist, produced short durations. Apomorphine also produced an increase in stabilimeter activity. These data suggest dopaminergic involvement in tonic immobility, and support a competing response interpretation of the apomorphine effect.

Animals↗
PubMed1979

Morphine potentiation of tonic immobility: effects of naloxone, PCPA, and 5,6-DHT.

The duration of tonic immobility in chickens, a catatonic-like state produced by brief restraint, was greatly potentiated by a single 1.0 mg/kg injection of morphine. Naloxone by itself, however, had no effect on tonic immobility, and only an exceptionally large dose of naloxone blocked the morphine potentiation. Pretreatment with PCPA and 5,6-dihydroxytryptamine completely eliminated the morphine enhancement. The effect of morphine on tonic immobility may be mediated by a central serotonergic-raphe system.

5,6-Dihydroxytryptamine↗
PubMed1979

Pargyline and tryptophan enhancement of tonic immobility: paradoxical attenuation with combined administration.

Four experiments were conducted to examine the individual and combined effects of pargyline and tryptophan on the duration of tonic immobility in chickens. Injection of either compound alone produced a dose-dependent potentiation of tonic immobility. However, combined administration of pargyline and tryptophan resulted in a dramatic attenuation of the response and this effect was completely blocked by pretreatment with p-chlorophenylalanine. In addition to reducing the duration of tonic immobility, combined administration of pargyline and tryptophan produced a complex behavioral syndrome which may be analogous to that observed in mammals after similar drug treatment. These results suggest the need for a modification of the recently proposed serotonergic-raphe model of tonic immobility.

Animals↗
PubMed1977

Tryptophan and tonic immobility in chickens: effects of dietary and systemic manipulations.

Consistent with a serotonergic-midbrain raphe model of tonic immobility, four experiments designed to affect changes in serum tryptophan produced reliable effects on the duration of the response in chickens. Systemic injections of tryptophan, the dietary precursor to serotonin, led to a dose-dependent increase in immobility, with optimal effects being observed within 30 min after injection. Dietary depletion of endogenous tryptophan served to attenuate the duration of immobility, and a diet completely free of tryptophan, but supplemented with niacin, practically abolished the reaction. Dietary replacement served to reinstate the response. In a fifth experiment, tryptamine, an alternative metabolic by-product of tryptophan, was found to have no effect on immobility. The data are discussed in light of evidence showing serotonergic involvement in tonic immobility.

Administration, Oral↗