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Biomedical subjects

A Gasbarri

Publications and source records attributed to A Gasbarri.

31 records · Page 2Linked to original sources
PubMed1994

Mesolimbic dopaminergic neurons innervating the hippocampal formation in the rat: a combined retrograde tracing and immunohistochemical study.

A major mesolimbic projection towards the hippocampal formation (HF) has been extensively described, but no clear evidence of its dopaminergic content has been demonstrated. In order to evaluate the percentage of dopaminergic (DA) cells of ventral tegmental area (VTA-A10) and adjacent substantia nigra (SN-A9) projecting to the HF, the retrograde neuronal tracer technique was combined with the tyrosine hydroxylase (TH) immunocytochemistry. Fluoro-gold (FG) was injected in several areas (subiculum, CA1, CA3, dentate gyrus) of either septal and temporal HF. Sections containing retrogradely FG labeled neurons were either mounted directly as controls or incubated with TH antiserum and revealed with rhodamine. The quantitative evaluation of retrogradely labeled and TH-IR stained cells showed that both VTA and SN projections towards the HF are partially (15-18%) dopaminergic. Ten percent of the DA neurons of the VTA projected to contralateral HF, whereas none did in the SN. In conclusion, the temporal HF (mainly subiculum and adjacent CA1) appears to receive the main DA afferents from both VTA cells and medial half of SN, pars compacta, whereas the septal HF (particularly CA1) receives its DA input from neurons located in the ventral half and in the upper and lower borders of the VTA.

Animals↗
PubMed1994

Anterograde and retrograde tracing of projections from the ventral tegmental area to the hippocampal formation in the rat.

Employing anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L), and a triple labeling protocol using retrogradely transported fluorescent tracers, we examined the projections from the ventral tegmental area (VTA-A10) to the hippocampal formation (HF) in the rat. Injections of PHA-L into VTA resulted in labeling in the ventral subiculum (stratum oriens and molecular layer) and in the adjacent CA1 field (stratum oriens, pyramidal, suprapyramidal and molecular layers) of HF. Additional labeling was observed in the stratum oriens of CA3 and in the hilus of fascia dentata. In the dorsal HF labeling was present in the subicular and CA1 field polymorphic layers. The distribution of VTA neurons projecting to the HF was also examined by injecting retrograde fluorescent tracers (Fluoro Gold, Fast Blue, and Nuclear Yellow) in several hippocampal areas. The most abundant VTA-HF projections originate from the upper and lower edges and the lower half of the VTA. These terminal fields in the HF match with the hippocampal areas projecting to the nucleus accumbens. The VTA, via projections to interconnected regions of the HF and nucleus accumbens, may modulate the hypothesized functional link between the limbic system and basal ganglia.

Animals↗
PubMed1993

Interaction of cholinergic-dopaminergic systems in the regulation of memory storage in aversively motivated learning tasks.

These experiments examined the interaction between muscarinic cholinergic and dopaminergic systems in the modulation of memory storage. Male CD1 mice (25-30 g) were trained in an inhibitory avoidance (IA) and a Y-maze discrimination (YMD) task. The first experiment examined the dose-response effects, on retention, of agonists and antagonists specific for either D1- or D2-receptors. Immediately posttraining mice were given i.p. injections of saline, the D1-receptor agonists SKF 38393 (3.0, 10.0 or 30.0 mg/kg) or SKF 77434 (3.0, 10.0 or 30.0 mg/kg), the D1-receptor antagonist SCH 23390 (0.03, 0.1, or 1.0 mg/kg), the D2-receptor agonist quinpirole (0.3, 1.0 or 3.0 mg/kg) or the D2-receptor antagonist sulpiride (3.0, 10.0, 30.0 or 100.0 mg/kg). Retention was tested 48 h later. The drugs affecting D1-receptors did not affect retention. In contrast, in both tasks quinpirole enhanced retention and sulpiride impaired retention. In the IA task, quinpirole (3.0 mg/kg) blocked the retention impairing effects of the muscarinic cholinergic antagonist atropine (10.0 mg/kg), and sulpiride (3.0, 10.0, 30.0 or 100.0 mg/kg) significantly attenuated the memory enhancing effects of the muscarinic cholinergic agonist oxotremorine (35.0 or 70.0 micrograms/kg). D1-receptor agents did not modify the effects of either atropine or oxotremorine on retention of the IA response. These findings suggest that the effects of cholinergic muscarinic agents on retention of the IA response are mediated by influences involving D2-dopaminergic mechanisms. In the YMD task, atropine (10.0 mg/kg) blocked the memory-enhancing effects of quinpirole (3.0 mg/kg) and oxotremorine (35.0 or 70.0 micrograms/kg) attenuated the memory impairing effect of sulpiride (3.0, 10.0, 30.0 or 100.0 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1991

Organization of the projections from the ventral tegmental area of Tsai to the hippocampal formation in the rat.

The projection from the ventral tegmental area of Tsai (VTA-A10) to the hippocampal formation (HF) has been investigated in the rat by means of the Fink-Heimer technique, after VTA destruction by electrolytic lesions or local injections of 6-hydroxydopamine (6-OHDA, 1 microgram/0.5 microliters). Degenerated axons prevail in the ventral subiculum and adjacent CA1 field. Some degenerated fibers are also observed in the dorsal subiculum and a few in the stratum oriens of the CA3, in the hilus of fascia dentata and in the fimbria. The distribution of VTA neurons projecting to the HF has also been examined by injecting retrograde fluorescent tracers in different combinations (Fast Blue, 2% and Nuclear Yellow, 1%) in several hippocampal areas. The most abundant VTA-HF projections originate from the lower third, the upper and lower edges and the lower half of the VTA. The major terminal fields of VTA projections in the HF (i.e. the ventral subiculum, the adjacent CA1 field and the dorsal subiculum) match with the HF area projecting to the nucleus accumbens. Thus, the dopaminergic meso-limbic pathway could modulate the HF-striatal projection which provides a link between the limbic and motor systems.

Animals↗
PubMed1989

[Projections of the Tsai tegmental ventral area to the hippocampus: a study of the rat using the Fink-Heimer technic].

The projection from the ventral tegmental area of Tsai (VTA-A10) to the hippocampal formation was investigated in the rat by means of the Fink-Heimer technique, after VTA destruction by electrolytic lesion or local injection of 6-hydroxydopamine (6-OHDA, 1 micrograms/0.5 microliters). Degenerated fibers are prevalently present in the ventral subiculum and CA1 field. These areas match with the area projecting towards the nucleus accumbens. Thus the dopaminergic meso-cortico-limbic pathway could modulate the HF-striatal projection which represents a link between the limbic and central motor systems.

Animals↗
PubMed1989

[Organization of the direct projections of the Tsai ventral tegmental area to the hippocampus].

In this report we have examined the distribution in the ventral tegmental area of Tsai (VTA-A10) of the neurons projecting to the hippocampal formation (HF) by injecting, in different combinations, retrograde fluorescent tracers (Fast Blue, 2% and Nuclear Yellow, 1%) in several hippocampal areas. The distribution of the VTA labeled neurons suggest a topographic organization of the VTA efferent pathway towards the HF. These results are in agreement with the concept that precise topography of the projections is a distinctive feature of the dopaminergic systems in general.

Animals↗
PubMed1987

The organization of nucleus tegmenti pedunculopontinus neurons projecting to basal ganglia and thalamus: a retrograde fluorescent double labeling study in the rat.

The organization of nucleus tegmenti pedunculopontinus (PPN) projections to the basal ganglia and thalamus was studied in the rat by using retrograde transport of fluorescent dyes. Fast blue was injected into the substantia nigra (SN) while Nuclear yellow was delivered to one of the following nuclei: globus pallidus (GP), entopeduncular nucleus, subthalamic nucleus (STN) or parafascicular nucleus of the thalamus. Retrogradely labeled cells were observed throughout the PPN without topographical arrangement. The cells labeled from the SN outnumbered those labeled from other structures. In all cases the majority of cells were single labeled and only a few cells double labeled from SN-GP or SN-STN were found. Labeled cells were either fusiform or multipolar in shape. These data suggest that distinct PPN cells project to their basal ganglia and thalamic targets without a prominent branched organization.

Amidines↗
PubMed1982

[Comparison of the growth of subjects from 6 to 12 years of age in the province of Naples and the province of L'Aquila].

The authors studied weight, height and thoracic circumference of 419 children 6 to 12 years old who were born in Naples county. They transcribed data on special anthropometrical forms and computed arithmetical mean and standard deviation for every series of biometrical values. Then they plotted the graphs of growth-state obtaining so the growth curves. Comparing these graphs with those obtained by the same methods in children from L'Aquila of the same age, the following conclusions can be drawn: 1) Neapolitan children have a slight more increased growth with respect to children born in L'Aquila; 2) the growth of both groups is similar since the shape of their growth curves is overlapping.

Anthropometry↗
PubMed1981

Neuroexcitatory properties of kainic acid. II) Neuronal damages following intracerebreal microinjections in behavioural rats.

Microinjection of low doses of kainic acid, a neurotoxic analogue of glutammate, in different brain areas (striatum, hippocampus, substantia reticularis pontis) induces neuronal damages in injected and distant areas. Particularly severe neuronal damages have been observed in striatum and CA3 hippocampal area; neuronal degeneration has also been observed in substantia nigra following kainic acid infusion into the substantia reticularis pontis.

Animals↗
PubMedDate not supplied

Task-dependent role for dorsal striatum metabotropic glutamate receptors in memory.

The effect of post-training intradorsal striatal infusion of metabotropic glutamate receptor (mGluR) drugs on memory consolidation processes in an inhibitory avoidance (IA) task and visible/hidden platform water maze tasks was examined. In the IA task, adult male Long-Evans rats received post-training intracaudate infusions of the broad spectrum mGluR antagonist alpha-methyl-4-carboxyphenylglycine (MCPG; 1.0, 2.0 mM/0.5 microL), the group I/II mGluR agonist 1-aminocyclopentane-1,3-carboxylic acid (ACPD; 0.5 or 1.0 microM/0.5 microL), or saline immediately following footshock training, and retention was tested 24 h later. In the visible- and hidden-platform water maze tasks, rats received post-training intracaudate infusions of ACPD (1.0 microM), MCPG (2.0 mM), or saline immediately following an eight-trial training session, followed by a retention test 24 h later. In the IA task, post-training infusion of ACPD (0.5 and 1.0 microM) or MCPG (1.0 and 2.0 mM) impaired retention. In the IA and visible-platform water maze tasks, post-training infusion of ACPD (1.0 microM), or MCPG (2.0 mM) impaired retention. In contrast, neither drug affected retention when administered post-training in the hidden-platform task, consistent with the hypothesized role of the dorsal striatum in stimulus-response habit formation. When intradorsal striatal injections were delayed 2 h post-training in the visible-platform water maze task, neither drug affected retention, indicating a time-dependent effect of the immediate post-training injections on memory consolidation. It is hypothesized that MCPG impaired memory via a blockade of postsynaptic dorsal striatal mGluR's, while the impairing effect of ACPD may have been caused by an influence of this agonist on presynaptic "autoreceptor" striatal mGluR populations.

Animals↗