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Biomedical subjects

L Pieri

Publications and source records attributed to L Pieri.

At least 37 records · Page 2Linked to original sources
PubMed1976

Changes of rat cerebellar guanosine 3',5'-cyclic phosphate by dopaminergic mechanisms in vivo.

Apomorphine produced a dose-dependent increase of the cGMP level in the cerebellum. Haloperidol and scopolamine completely prevented this increase, and reserpine reduced the increase to 50%. LSD elevated cerebellar cGMP, and this effect was also abolished by haloperidol. It is suggested that the primary site of action of these drugs is the caudate nucleus, from which two neuronal pathways could trigger the increase of cGMP in the cerebellum.

Animals↗
PubMed1975

Disappearance of supra-ependymal 5-HT axons in the rat forebrain after electrolytic and 5,6-DHT-induced lesions of the medial forebrain bundle.

The present study was intended to demonstrate the origin of supra-ependymal 5-hydroxytryptamine axons in the rat forebrain. Electrolytic lesions and injections of 5,6-dihydroxytryptamine (10 mug in 4 mul) were carried out unilaterally in and close to the medial forebrain bundle in the posterior hypothalamus of rats. Ten to 14 days later, terminal axons and formaldehyde-induced indolealkylamine fluorescence had virtually disappeared supra-ependymally in the lateral ventricles and interventricular foramina ipsilateral to the lesion if the indolealkylamine axons passing through the medial part of the medial forebrain bundle had been destroyed. No changes were observed, electron microscopically or fluorescence histochemically, in ventricles contralateral to the lesion. It is concluded that the supra-ependymal serotonergic nerve terminals in the lateral ventricles and interventricular foramina originate, uncrossed, from non-terminal axons passing through the medial forebrain bundle in the posterior hypothalamus.

5,6-Dihydroxytryptamine↗
PubMed1975

Improved rapid method to check electrode localizations in the brain.

A modification of known rapid methods to check electrode localization in the brain is described: the essential point consists in immersing the brain, after fixation in 4 percent Formalin, in pure heptane at -30 degrees C for 5 hr. Unstained sections, cut with the freezing microtome, are placed uncovered on glass slides and photographed (in an enlarger, as if they were negatives) either wet, to obtain a contrast resembling Weil staining, or dry, to obtain a picture corresponding to Nissl staining.

Animals↗
PubMed1975

A comparison of drug-induced rotation in rats lesioned in the medial forebrain bundle with 5,6-dihydroxytryptamine or 6-hydroxydopamine.

Drug-induced rotational behaviour was studied in two groups of rats with differing chemical lesion of the right medial forebrain bundle (MFB). 6-hydroxydopamine (6-OH-DA), 3.5 mug, injected in one group, induced a marked lowering of dopamine (DA) and noradrenaline (NA) in the right hemiforebrain. 5,6-Dihydroxytryptamine (5,6-HT), 10 mug, injected in a second group, produced a profound and long-lasting depletion of 5-hydroxytryptamine (5-HT) and DA, but not of NA. Rotational behaviour induced in both groups by DA receptor agonists (apomorphine, piribedil, L-DOPA, ergometrine, ergocornine, 2-bromo-alpha-ergocryptine, ergocristine, methylergometrine) and agents releasing DA (d-methamphetamine, methylphenidate) were qualitatively identical and quantitatively very similar, suggesting a minor role of 5-HT striatal terminals in these experimental conditions. LSD induced contralateral rotation by direct stimulation of the DA receptor, while L-5-hydroxy-tryptophan (L-5HTP) was inactive.

5,6-Dihydroxytryptamine↗
PubMed1975

Possible involvement of GABA in the central actions of benzodiazepines.

The effects of several benzodiazepines on a variety of nervous activities known or presumed to depend on GABA are presented and compared with those of agents that deplete or increase the level of endogenous GABA: antagonism of various convulsant agents in mice, enhancement of presynaptic inhibition in the spinal cord and the cuneate nucleus of cats, decrease of the spontaneous firing rate of cerebellar Purkinje cells in cats and rats, antagonism of bicuculine-induced depression of the strio-nigral-evoked potential in the cat, potentiation of haloperidol-induced catalepsy in rats, GABA-mimetic actions on drug-induced PGO-waves in cats and on eserine-induced circling in guinea pigs. Diazepam slightly increased the GABA level in the cat spinal cord and in the total brain of mice and rats; this increase does not seem to be due to an increase of GABA synthesis. It is concluded that benzodiazepines probably enhance presynaptic inhibition at all levels of the neuraxis and that this effect requires not only the presence of GABA but is also dependent on an activity of GABA-ergic neurons. Benzodiazepines also appear to enhance postsynaptic inhibition where this is mediated by GABA. Many actions of benzodiazepines can be tentatively explained by a stimulus-bound enhancement of GABA effects.

Aminobutyrates↗
PubMedDate not supplied

[Digital videoradiography applied to the study of the recto-anal region during defecography].

The authors have employed a real-time fluoroscopic computerized equipment during defecography. Digitalized images were acquired at a rate of three frames/s and then processed and became immediately available. Digital defecography was employed in 67 patients with various anorectal diseases--i.e., rectocele, descending perineum, rectal prolapse, non-relaxing puborectalis syndrome and fecal incontinence. We found time-interval difference (TID) technique especially useful for it allowed different functional phases of defecation to be depicted on a single subtracted image and an evaluation of the movements of anorectal region. The high contrast resolution of the computerized equipment demonstrated even minimal contrast medium leaks in fecal incontinence. The examination is easy and rapid to perform with a low radiation dose to the patients.

Defecation↗
PubMedDate not supplied

[Digital subtraction radiology in the study of mobile structures of the larynx].

Digital subtraction radiography (DSR) was applied to the study of the larynx in 11 healthy subjects and 15 pathological cases. The method, consisting in the subtraction of images obtained at rest and during phonation or respiratory phases, allowed a clear definition of the normal moving structures--i.e. vocal cords, false cords, pyriform sinuses, thyroid cartilage. Moreover, several pathological conditions could be demonstrated. DSR asserts thus itself as a suitable technique in the functional evaluation of the glottis.

Fluoroscopy↗