Apparent lack of a dopaminergic-cholinergic link in the rat nucleus accumbens septi-tuberculum olfactorium

The nucleus accumbens septi and tuberculum olfactorium (NAS-TO), which from part of the mesolimbic dopaminergic system, and the striatum, which is part of the nigrostriatal dopamingeric system, contain high levels of both dopamine (DA) and acetylcholine and resemble each other in some other biochemical properties. We determined whether blockade or stimulation of DA receptors by agonists or antagonists affects the cholinergic neurons in this brain structure. The DA receptor antagonists haloperidol, pimozide, chlorpromazine and clozapine had no effect on the acetylcholine level in the NAS-TO even at 2-8 times the minimum dose required to maximally decrease striatal acetylcholine. Similarly, D-amphetamine and bromocriptine (CB 154), DA receptor stimulating drugs, had no effect on the acetylcholine level in this brain area at doses up to 3 times higher than those that produced a maximum increase in the striatum. Piribedil (15-120 mg/kg) and apomorphine (4 mg/kg) did increase acetylcholine in the NAS-TO but the action was not blocked by pimozide and is therefore not attributable to DA receptor action. The data thus indicate an apparent lack of a dopaminergic-cholinergic link in the NAS-TO.

The cerebrospinal fluid choline levels in patients with Huntington's chorea. Negative effect of haloperidol treatment

Lumbar cerebrospinal fluid (CSF) choline (CH) levels were measured in patients with Huntington's chorea (n = 14). This group was found not to differ significantly from normal controls (n = 13). The values for lumbar CSF Ch levels in the normal subjects were comparable with previously reported values. Of the choreic patients, seven were put on haloperidol treatment (4--6 mg daily). The CSF choline level remained unchanged with this treatment after 20 days. CSF cholinesterase activity was measured in the control and choreic group. The results were not significantly different.

[Frequency of malocclusion in 800 school children in the province of Pavia]

After a brief review of the literature on the subject, the results of a study of the frequency of malocclusions in 800 primary school children are reported. A very high percentage (80.3%) was observed, with a prevalence of males(83%) over females (77%). The relationships between malocclusions and age and between malocclusions an; caries are also examined.

[Osteopetrosis (Albers-Schönberg disease). I. Clinico-radiological and pathogenetic aspects]

An account is given of recent clinical and radiological findings with respect to Albers-Schönberg disease. Reference is made to its hereditary transmission modality and clinical picture (skeletal lesions and haematological distress), and to its radiological aspects. Suggestions are made with respect to the aetiopathogenesis of disease. Stress is laid on the as yet undefined mechanism of "genotypical condensing dysplasia". The relation between osteopetrosis and thyrocalcitonin is discussed, though no definite conclusions could be drawn from the hormone levels determined in a personal series.

[Thermography in lymphomas]

Thermography was carried out in 28 cases of lymphomas of the superficial lymphnodes. Hyperthermia of lymphnodes that are the site of an active lymphomatous process and its arrest following effective, especially radio, therapy has been confirmed.

[A simple injector for direct lymphography]

A gas pressure injector for easy lymphography is described; skilled personnel are not required, cost is very low and operation reliable. The injector has been used without problems in 300 abdominal lymphographies.

Increase in striatal acetylcholine by picrotoxin in the rat: evidence for a gabergic-dopaminergic-cholinergic link

Picrotoxin, 2 mg/kg i.p., a GABA receptor blocking agent, increased rat striatal acetylcholine content by approximately 70% without altering the levels of this amine in the cerebral hemispheres, mesencephalon, diencephalon, hippocampus and cerebellum. Striatal choline levels were concomitantly decreased by about 25%. This dose of picrotoxin also increased striatal homovanillic acid levels by about 30%, an effect which was not antagonized by pretreatment with the dopamine receptor stimulating agent, piribedil. Picrotoxin did not affect striatal choline-O-acetyltransferase or cholinesterase activity after in vitro incubation. The action of picrotoxin on striatal acetylcholine levels was partially antagonized by pimozide and completely blocked by alpha-methyl-para-tyrosine pretreatment while the intraventricular injection of 6-hydroxydopamine was without effect. Convulsions were not prevented by any of these treatments. The results are interpreted as follows: picrotoxin released dopamine through disinhibition of the dopaminergic neurons as a result of blockade of gabergic receptors. The increased dopaminergic activity inhibited cholinergic neurons and lead to an increase in acetylcholine content. The data thus provide evidence for a possible gabergic (inhibitory)--dopaminergic (inhibitory)-cholinergic link terminating in the striatum.

Lack of influence of the phase of estrus cycle or treatment with steroid contraceptive drugs on cholinergic parameters in mouse and rat brain

Acetylcholine and choline levels were found not to fluctuate with the phase of the estrus cycle in the cerebral hemispheres, deincephalon and mesencephalon in the rat and mouse. Choline acetyltransferase activity was not altered in these brain areas in the mouse while in the rat there was a small but significant decrease in the cerebral hemispheres during proestrus (p less than 0.01), and in the mesencephalon during estrus (p less than 0.05), both with respect to diestrus. Chronic 30-day treatment with steroid contraceptive drug combinations (lynestrenol, 5 mg/kg+ mestranol, 0.3 mg/kg; lynestrenol, 2.5 mg/kg+ mestranol, 0.15 mg/kg; norethindrone, 4 mg/kg+ mestranol, 0.2 mg/kg; norethynodrel, 4 mg/kg+ mestranol, 0.06 mg/kg) did not alter cholinergic parameters in the brain areas of these two species except for minor changes in rare instances.

Decrease in rat striatal acetylcholine levels by some direct- and indirect-acting dopaminergic antagonists

Several direct- or indirect-acting dopamine receptor antagonists were found to decrease rat striatal acetylcholine levels. The maximum decrease of about 50% was produced by pimozide (0.5 mg/kg), by haloperidol (0.5 mg/kg) and by reserpine (2.5 mg/kg). The decreases in acetylcholine produced by pimozide and by haloperidol were found to be specific for the striatum and did not alter diencephalonic, mesencephalonic, cerebellar or hemispheric acetylcholine levels. Furthermore, these two drugs completely blocked the increase in striatal acetylcholine produced by the dopamine receptor agonist, apomorphine, and had no effect on striatal choline acetyltransferase and cholinesterase. These data suggest that haloperidol and pimozide act on the striatal cholinergic neurons through strong blockade of dopamine receptors. Reserpine presumably decreased striatal acetylcholine levels indirectly by depleting biogenic amines. Clozapine and 1-fenfluramine were unable to block the action of apomorphine, as was shown previously for chlorpromazine. It is thus suggested that these drugs are reversible dopamine receptor antagonists. Their weaker action in decreasing striatal acetylcholine may depend upon this property.

Cholinergic-dopaminergic interaction in the striatum: the effect of 6-hydroxydopamine or pimozide treatment on the increased striatal acetylcholine levels induced by apomorphine, piribedil and d-amphetamine

Apomorphine (1 and 2 mg/kg), piribedil (15 and 60 mg/kg) and d-amphetamine (5 and 10 mg/kg) increased rat striatal acetylcholine levels without affecting choline. Pretreatment with pimozide (0.5 mg/kg) completely antagonized the effect of apomorphine and piribedil and by itself markedly decreased striatal acetylcholine levels. d-Amphetamine signigicantly antagonized the effect of pimozide. Nine days after pretreatment with 6-hydroxydopamine plus pargyline, striatal dopamine was decreased by 78% while acetylcholine and choline levels remained unaltered. Under these conditions, the effect of d-amphetamine was completely abolished while apomorphine and piribedil were just as active as in the vehicle-treated group. The results suggest that d-amphetamine acted indirectly to increase striatal acetylcholine levels probably through the release of dopamine and/or noradrenaline, while apomorphine and piribedil acted directly at dopamine receptor sites.