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Biomedical subjects

S Consolo

Publications and source records attributed to S Consolo.

At least 109 records · Page 6Linked to original sources
PubMed1980

Comparison of the effects of the stereoisomers of fenfluramine on the acetylcholine content of rat striatum, hippocampus and nucleus accumbens.

The (+)- and (-)- isomeric forms of fenfluramine were compared for their effects on rat brain area acetylcholine (ACh) content. The drugs showed similar patterns in increasing ACh content in the accumbens and hippocampus and in being ineffective in the brainstem. The actions differed in the striatum where the (+)-form markedly increased ACh content while the (-)-form produced no change. Both isomer-induced increases in ACh in the accumbens were prevented when 5-HT synthesis was blocked by p-chlorophenylalanine, thus denoting 5-hydroxytryptaminergic mediation of these effects. In striatum, the increase in ACh induced by (+)-fenfluramine was summated with the increase in ACh induced by dopamine receptor stimulation with apomorphine and was not prevented by dopamine receptor blockade with pimozide. On the other hand, apomorphine's effect was blocked by (-)-fenfluramine while pimozide pretreatment unmasked an increase in ACh induced by (-)-fenfluramine. The results favour the notion that there is a population of cholinergic neurons intrinsic to the striatum which is under inhibitory 5-HT regulation and independent of inhibitory dopamine regulation.

Acetylcholine↗
PubMed1980

[Sinus arrhythmia: quantitative evaluation and possible use in the diagnosis of sick sinus syndrome (author's transl)].

This research was done in order to quantify the sinus arrhythmia and to determine any possible quantitative difference between normal subjects and patients with Sick Sinus Syndrome (SSS). The ECG of 200 normal subjects and 30 patients with SSS diagnosed with electrophysiologic evaluation have been studied. 50 consecutive PP intervals have been measured in each ECG, and the average and standard deviation (SD) were calculated. The variableness of the sinus cycle was expressed by the Sinus Arrhythmia Index (SAI), obtained by the ratio between the SD and the average length of the cycle. It was observed that in normal subjects the SAI decreases with aging, and its value is not related to the heart rate. The SAI was significantly higher in the patients with SSS than in the normal ones. Since a sinus arrhythmia of high degree may be observed in the SSS, the quantitative evaluation of this arrhythmia, obtained by the index we proposed, may be useful to the detection of this syndrome.

Aged↗
PubMed1980

[Atrial dissociation simulated by respiratory artifacts. Case report].

A case of likewise atrial dissociation in a twelve years old patient affected by mucovisclosis with severe respiratory failure is described. The classic criteria of the atrial dissociation were met in the ECG, in which, beside the sinus P waves, low P-like waves, whose rate was 69/m', were present: they did not conduct to the ventricles and were independent from the sinus rhythm. Such waves always coincided with the beginning of the inspiration, and disappeared during the apnoea. So they were not believed as being the results of electrical forces of the heart, but artifacts produced by respiratory movements. The diagnostic criteria of the atrial dissociation are discussed on the basis of these observations. the exclusion of artifacts, especially the respiratory ones, and the demonstration, obtained through the intracavitary ECG, that the waves are really produced by the heart, are necessary to diagnoses the arrhythmia. By the application of these diagnostic criteria only one of the cases found in the Literature has been accepted as demonstrative of atrial dissociation due to complete intraatrial block in man.

Child↗
PubMed1978

Storage and release of acetylcholine in the isolated superior cervical ganglion of the rat.

The storage and release of acetylcholine and choline were studied in the isolated superior cervical ganglion of the rat by a radioenzymic method. The acetylcholine and choline contents were 202.2 +/- 5.1 and 624.7 +/- 20.2 pmole/ganglion, respectively. The transmitter tissue store was unaffected during 1 h of superfusion in choline--Krebs solution, while a 20% decrease was exhibited after 2 h and then remained approximately stable. Conversely, choline content declined to 50% within 1 h and further to 37% of the original level by 4 h. About 24% of the choline assayed in the intact preparation is located in the connective sheath. Preganglionic nerve stimulation at 10--20/sec or potassium stimulation (40 mM KCl) invariably decreased the transmitter tissue stores by 25--45%; such a depletion is independent of the presence or absence of external choline. By contrast, the presence of choline proved to be a prerequisite for the efficient release of acetylcholine from eserinized ganglia during continuous 10/sex stimulation. A drastic depression in the acetylcholine release is described which is related to the time of preincubation of the ganglia with eserine prior to stimulation. Indeed, a 30 min exposure to eserine, compared with a 5 min period, resulted in a 4-fold decrease in the steady output rate. Under optimal conditions, the initial volley output at 10/sec was 1.3 X 10(-4) of the releasable transmitter pool and 1.9 X 10(-4) during the steady-state output. These results are discussed in the light of the electrophysiological knowledge of the quantal release process at the ganglionic synapse.

Acetylcholine↗
PubMed1977

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.

Acetylcholine↗
PubMed1977

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.

Adult↗
PubMed1976

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.

Acetylcholine↗