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Query: UMLS:C0033377 (prolapse)
 11,717 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Alterations in regional energy metabolism in rat brain produced by small and by large doses of apomorphine: possible relations to autoreceptors. 282 Jul 57

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)
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PMID:Conditioning of pre- and post-synaptic behavioural responses to the dopamine receptor agonist apomorphine in rats. 302 94

Apomorphine, in an intermediate dose (0.18 mg/kg s.c.) decreased dopamine turnover and produced signs generally attributed to a decrease in dopaminergic neurotransmission, e.g. ptosis and yawning, as well as signs of an increased stimulation of dopamine receptors in dopaminoceptive target neurones, e.g. stereotyped sniffing. In contrast, the former signs were exclusively observed after smaller doses and the latter after larger doses of apomorphine. Since it had been shown in previous studies that these signs, except yawning, could be conditioned in association with discriminative stimuli in the environment, the present study using conditioning experiments with this intermediate dose aimed at determining, 1. the time course of each conditioned response, 2. the interaction of conditioned and unconditioned responses, and 3. the conditions under which hypokinesia occurred. In each series, conditioned animals were compared with pseudoconditioned controls. Rats were conditioned for 8 days with apomorphine, and on day 9, treated with saline in presence of the conditional stimuli (a test cage in combination with acoustic and olfactory stimuli). In contrast to pseudoconditioned controls, ptosis and stereotyped behaviour were observed in conditioned rats, sometimes occurring alternatingly. These signs closely resembled the direct, unconditioned pharmacological effects. In addition, akinesia occurred after conditioning, although it was never manifest as a pure drug response, nor during the conditioning period. In contrast, yawning was observed in pseudoconditioned as well as in conditioned rats, although slightly more frequently in the former animals. Subsequently, the rats were again conditioned (or pseudoconditioned) on days 10-14 with apomorphine and both groups tested with the same dose (0.18 mg/kg) of apomorphine in the presence of the conditioned stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Conditioning of behavioural effects produced by an intermediate dose of apomorphine: hypokinesia, ptosis and stereotypies. 368 96