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H G Möller

Publications and source records attributed to H G Möller.

9 recordsLinked to original sources
PubMed1987

Alterations in regional energy metabolism in rat brain produced by small and by large doses of apomorphine: possible relations to autoreceptors.

Dose-dependent changes in behavioural patterns and in local cerebral glucose utilization (LCGU) following subcutaneous application of apomorphine were measured in conscious, unrestrained rats by means of a scoring system and of the autoradiographic [C14]2-deoxyglucose technique, respectively. The behavioural patterns of akinesia, ptosis, yawning and penile erections were scored. Akinesia and ptosis were most prominent after 0.02 and 0.07 mg/kg apomorphine but not after 0.18 mg/kg. Maximal scores for yawning and penile erections were obtained after 0.07 mg/kg. LCGU was not significantly changed after 0.07 mg/kg except for decreases in the cingulate cortex and hypothalamus. Apomorphine 0.5 mg/kg decreased LCGU in the cingulate, parietal and occipital cortex, anteromedial and lateral thalamus and lateral habenula but increased it in laminae IV and VI of the sensorimotor cortex, in the parafascicular nucleus of the thalamus, and in some parts of the basal ganglia and related nuclei. Similar changes in LCGU occurred after 2.0 mg/kg apomorphine, which also increased LCGU in the ventral tegmental area. The lower dose did not produce changes in LCGU opposite to those occurring after larger doses. The data obtained with LCGU do not support the idea that behavioural effects after low doses of apomorphine are elicited by activation of dopamine autoreceptors.

Animals↗
PubMed1987

Studies on interactions between conditioned and unconditioned behavioural responses to apomorphine in rats.

Interactions between the direct (unconditioned) behavioural effects apomorphine and its conditioned effects after pairing with previously neutral stimuli were studied. Rats were injected once daily for 3-12 times, with apomorphine (2.0 mg/kg or 0.5 mg/kg or 0.07 mg/kg s.c. the dose kept constant in each series), in the presence of defined environmental stimuli (a wire cage in association with an acoustic and an olfactory stimulus) as conditional stimuli. The two larger doses produced stereotyped sniffing, licking, and gnawing, the smallest dose akinesia, ptosis, yawning and penile erections. During the conditioning phase, the drug produced most of the effects with increasing intensity and in the case of the stereotypies, there also was a shift to higher scores of stereotypy, with a reduced latency in onset of the signs. On the test day, 1 day after the last administration of apomorphine, the conditioned rats as well as "pseudoconditioned" controls were treated with a test dose of apomorphine in the presence of the conditional stimuli. Pseudoconditioned rats had been treated with the same pharmacological schedule of apomorphine and had the same familiarity with the stimuli, but both were kept separate. A test dose of 0.5 mg/kg of apomorphine produced stereotypies with a significantly higher score and shorter latency in onset in conditioned than in pseudoconditioned rats. Rats conditioned with the lowest dose showed a significantly longer total duration and a shorter latency in onset of akinesia and ptosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Conditioning of behavioural signs produced by nomifensine and by B-HT 920 in rats.

Conditioning of behavioural effects produced by two drugs acting differently upon dopaminergic neurotransmission was studied. Nomifensine and the putative dopamine autoreceptor agonist B-HT 920 produce contrasting effects on motility, namely increases in locomotor activity and stereotypies as compared to hypokinesia and ptosis. The administration of each of these drugs (US) was repeatedly associated with well-defined environmental stimuli (CS): a wire cage associated with an auditory and on olfactory stimulus. The rats were conditioned for 7 days with 20 mg/kg nomifensine IP each day. After conditioning, the rats were treated with the solvent alone in presence of the CS. Not only did sniffing and licking occur, but also gnawing, even though the latter response was not evident after acute administration of the drug or during the conditioning period. Nomifensine (20 mg/kg IP) also acutely decreased the ratio of 3,4-dihydroxyphenylacetic acid/dopamine concentrations (DOPAC/DOPAMINE); this ratio was not altered in the conditioned rats, 60 min after solvent administration in presence of the CS. Rats were conditioned with 0.02 mg/kg IP B-HT 920 daily for 8 days. During the conditioning phase, akinesia and ptosis showed a slight enhancement and a faster onset. After conditioning, when the rats were treated with the solvent alone, the majority of them showed akinesia and/or ptosis during the observation period, in contrast to pseudoconditioned controls. When these rats were conditioned or pseudoconditioned, respectively, with B-HT 920 for further 5 days using 0.02 mg/kg again, treatment with the same dose in presence of the CS produced a significant enhancement and acceleration of these signs in conditioned as compared with pseudo-conditioned control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Conditioning of pre- and post-synaptic behavioural responses to the dopamine receptor agonist apomorphine in rats.

We investigated whether pharmacological effects of the dopamine agonist apomorphine can be conditioned by establishing an association of apomorphine administration with exteroceptive cues. Apomorphine was repeatedly administered and subsequently, the rat was put into a test cage and exposed to an acoustic and an olfactory stimulus ("conditioned rats"). Control animals ("pseudoconditioned" rats) were treated with the same pharmacological schedule of apomorphine not temporally associated with the stimuli. On the test day, both groups were injected with saline and exposed to the stimuli described. The stereotyped behaviour produced by large doses of apomorphine (0.5 or 2.0 mg/kg SC), namely sniffing, licking and gnawing, could be conditioned in a pronounced way. During the conditioning period, a change in the stereotypies was observed with regard to the time-course (earlier occurrence) and to the character of the stereotypies (from sniffing to licking and gnawing), when 0.5 mg/kg apomorphine was used, but not with the dose of 2.0 mg/kg. The conditioned responses showed a relatively uniform distribution during the observation period with some increase towards the end of the observation period. Some signs produced by a low dose of apomorphine (0.07 mg/kg SC), namely hypomotility and ptosis, but not yawning, could also be conditioned, although in a less pronounced way. An intermediate dose of apomorphine (0.18 mg/kg SC) produced both signs observed after large doses and those observed after a small dose, occurring alternatingly. Both types of signs could be conditioned using this dosage. Conditioning did not alter striatal or mesolimbic dopamine turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Individual and morphological differences in the behavioural response to apomorphine in rats.

The topography of stereotyped behaviour produced by apomorphine in rats was studied by using either a scoring system, based on observation in a wire cage, or by quantification of horizontal and vertical activities, and of the total distances run in an open field, using an automatic recording system. The latter design was combined with a classification of the type of stereotyped behaviour observed during recording. In addition, the reproducibility of the nature of the stereotyped behaviour and its dose-dependence in individual animals was evaluated. In rats observed in a wire cage, apomorphine at lower doses (0.25 or 0.50 mg/kg SC) produced stereotyped sniffing. Increasing the doses led to stereotyped licking and the largest dose (5.00 mg/kg SC) produced predominantly stereotyped gnawing, as was demonstrated graphically. The type of behaviour produced by 2 mg/kg apomorphine in the open field was reproduced well in individuals after a second administration 4 days later. The shift from sniffing to gnawing was observed in most, but not all of the individually classified animals after administration of the largest dose (5 mg/kg). The locomotor part of motility was highest in "sniffing animals" and lower when gnawing occurred. The non-locomotor part of motility was low in "sniffing rats" and increased when licking and gnawing occurred. In some of the animals a characteristic "climbing" behaviour was observed in addition after the larger doses, which did not interfere with sniffing, licking or gnawing. A combination of classification by observation and automatic recording seems the most appropriate way to study the topography of stereotyped behaviour produced by apomorphine.

Animals↗
PubMed1986

Interactions of morphine with apomorphine: behavioural and biochemical studies.

The interactions of morphine with the agonist at dopamine receptors apomorphine were studied on the behavioural and biochemical level. Apomorphine (0.5 mg/kg s.c.) produced stereotyped sniffing and some licking behaviour. Pretreatment with morphine enhanced licking behaviour and, in addition, produced some gnawing behaviour, a sign which is seen after a larger dose of apomorphine alone as well. This enhancement by morphine was maximal after 3.3 mg/kg i.p. and less pronounced after smaller or larger doses of morphine; naloxone (1 mg/kg i.p.) antagonized the enhancement. Morphine did not affect the decrease in the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC) produced by apomorphine in striatum and nucleus accumbens. In contrast, morphine increased the concentration of 3-methoxytyramine (3-MT) in both areas after pretreatment with pargyline (75 mg/kg i.p.), suggesting that it increased the release of dopamine, which might explain the enhancement of apomorphine-induced stereotyped behaviour. The enhancement by morphine of stereotyped behaviour produced by lisuride (2 or 4 mg/kg i.p.), another agonist at dopamine receptors, was much less pronounced than on apomorphine-induced stereotypies.

Animals↗