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A Benigno

Publications and source records attributed to A Benigno.

At least 19 recordsLinked to original sources
PubMed2006

Selective activation of 5-HT(2C) receptors stimulates GABA-ergic function in the rat substantia nigra pars reticulata: a combined in vivo electrophysiological and neurochemical study.

In vivo electrophysiology and microdialysis were used to investigate the physiological role of 5-HT(2C) receptors in the control of substantia nigra pars reticulata (SNr) function. Extracellular single-unit recordings were performed from putative GABA-containing neurons in the SNr of anesthetized rats, and local GABA release was studied by in vivo microdialysis in the SNr of awake freely-moving rats. Systemic administration of the selective 5-HT(2C) receptor agonist (S)-2-(chloro-5-fluoro-indol-1-yl)-1-methylethylamine 1:1 C(4)H(4)O(4) (RO 60-0175) caused a dose-dependent excitation of about 30% of the SNr neurons recorded. However, the remaining neurons were either inhibited or unaffected by systemic RO 60-0175, in similar proportion. Local application of RO 60-0175 by microiontophoresis caused excitation in the majority of SNr neurons tested (48%), whereas a group of neurons was inhibited (16%) or unaffected (36%). Both the excitatory and the inhibitory effects of systemic and microiontophoretic RO 60-0175 were completely prevented by pretreatment with SB 243213 [5-methyl-1-({2-[(2-methyl-3-pyridyl)oxy]-5-pyridyl}carbamoyl)-6-trifluoromethylindoline], a selective and potent 5-HT(2C) receptor antagonist. Consistent with these electrophysiological data, both systemic and intranigral administration of RO 60-0175 and m-chlorophenylpiperazine (mCPP), a non-selective 5-HT(2C) agonist, markedly increased extracellular GABA levels in the SNr. The stimulatory effect of systemic and local RO 60-0175 on GABA release was completely prevented by systemic administration of SB 243213, whereas local application of SB 243213 into the SNr only partially blocked RO 60-0175-induced GABA release. It is concluded that selective activation of 5-HT(2C) receptors stimulates GABA-ergic function in the SNr, and the clinical relevance of these data is discussed.

Action Potentials↗
PubMed1999

Myelodysplastic syndrome with atypical eosinophilia in association with ring chromosome 7. A case report.

The presence of morphologically abnormal eosinophils in the bone marrow and/or peripheral blood has been rarely reported as a prominent feature in myelodysplastic syndromes (MDS). Specific chromosomal aberrations have been observed in such cases. We report a case of a 76-year-old man who presented with chronic, transfusion-dependent anemia. Peripheral blood smear analysis revealed anisocytes, mild leukopenia, and occasional hypersegmented eosinophils. A subsequent bone marrow biopsy and aspiration disclosed hypercellularity, and morphologic abnormalities within the megakaryocyte, erythroid, and myeloid series. The myeloid population was predominantly comprised of eosinophils with varying degrees of dyspoiesis. The constellation of hematologic findings were without a precise categorization according to the FAB classification of myelodysplastic syndromes. Subsequent cytogenetic techniques demonstrated a ring chromosome 7 in all 20 metaphases analyzed in cultured bone marrow cells. Eighty-five-percent of the analyzed cells showed a ring chromosome composed of both the long and short arms: r(7)(p22q36). In the remaining metaphases, the ring was composed of only the short arm: r(7)(p22q10). To our knowledge, these uncommon cytogenetic abnormalities have not been previously reported in association with MDS with morphologically atypical bone marrow or peripheral eosinophilia.

Aged↗
PubMed1995

[6 cases of small intestine lymphoma].

The Authors report six cases of primitive and secondary intestinal lymphomas. Surgical radicality was achieved only in three of them. In the other cases surgical resection carried out in emergency and late histological diagnosis did not allow a correct surgical treatment. Peri-operative mortality was 16%. Five patients underwent adequate radiation and chemo-therapy programme. Recurrences, secondary localizations, or other neoplasms elsewhere, require a prolonged follow up period for these patients.

Adolescent↗
PubMed1994

Isolation and characterization of conditionally immortalized astrocyte cell lines derived from adult human spinal cord.

As an approach to develop both oligodendrocytic and astrocytic cell lines from adult human spinal cord, a cellular preparation of highly enriched oligodendrocytes and their precursors was infected with a replication-deficient retrovirus containing DNA sequences encoding the temperature-sensitive mutant of SV40 large T antigen. Six immortal cell lines were obtained. At both permissive (33 degrees C) and non-permissive (38.5 degrees C) temperatures, all cell lines were positive for vimentin, two demonstrated glial fibrillary acidic protein (GFAP) immunoreactivity, and none expressed oligodendrocyte or microglial markers. The 2 GFAP-positive cell lines [human spinal cord (HSC)2 and HSC6] were further characterized. Karyotype analysis revealed that both HSC2 and HSC6 cells showed gain of chromosomal material and structural chromosomal abnormalities. However, at non-permissive temperature both cell lines were indistinguishable from primary human astrocytes by a number of criteria. These properties included glutamine synthetase activity, Na(+)-dependent glutamate uptake, K+ flux, purine-evoked Ca2+ mobilization and entry, and the ability to support neurite outgrowth from embryonic rat retinal explants. The HSC2 and HSC6 cell lines may prove to be valuable models for studying the physiological properties of adult human astrocytes.

Adult↗
PubMed1989

Circling behavior: ethological analysis and functional considerations.

Head-turning and circling movements evoked by substantia nigra (pars compacta) (SNpc) stimulation have been ethologically analyzed in order to attribute a functional meaning to these lateralization processes. It has been shown that these motor acts, separated by a constant interval, may be considered a fixed action pattern. The duration of the single acts depends on the SNpc stimulation parameters: the increase in the stimulus strength produces an increase in the number of turns but does not induce the disappearance of the orientation movement. The body movement is always preceded by the head-movement. Haloperidol administration induces a dose-related increase of the orientation component of the motor pattern. These data together with others in the literature suggest the participation of the SNpc in the mechanism of shift in the focus of attention from one point to another in the contralateral surrounding environment.

Animals↗
PubMed1989

The influence of dopaminergic A10 neurons on the motor pattern evoked by substantia nigra (pars compacta) stimulation.

The influence of the mesolimbic-mesocortical dopaminergic (DA) system on the motor pattern evoked by substantia nigra pars compacta (SNpc) stimulation was studied. Electrical stimulation of the A10 group of neurons caused an inhibitory effect preferentially directed towards the orientation movement. Sulpiride administration at low dosages (50 mg/kg i.p.) did not modify this movement at the basal condition, but abolished the increase of its duration induced by ventral tegmental area (VTA) co-stimulation. Mesolimbic activation opposes the effects of SNpc stimulation, restraining the animal in its antero-posterior axis by means of orientation movement inhibition. The results suggest a role of the DA mesolimbic-mesocortical system in the maintenance of focused attention.

Animals↗
PubMed1988

Facilitatory effect of ventral tegmental area A10 region on the attack behaviour in the cat: possible dopaminergic role in selective attention.

Lateral hypothalamus (LH) stimulation in cats which do not spontaneously attack rats, produces an attack pattern which may be divided into 3 main stages: the first, defined as exploratory time (ET), begins with an environmental search and culminates in orienting towards the prey; in the second, defined as attack time (AT), the cat stalks the rat; the last is the biting stage in which the cat seizes and kills the prey by biting its head and neck. The effects of ventral tegmental area (VTA) stimulation on the latency of the whole sequence and on the different stages of the attack pattern were studied. VTA activation resulted in a significant decrease of biting latency, due to the reduction of exploratory time. Moreover, a significant period of prey fixation, seldom present during LH stimulation alone, was observed after VTA-LH co-stimulation. Sulpiride injection caused the disappearance of VTA effects on the predatory pattern. The results indicate that VTA activation induces a decrease in behaviour related to exploration of the environment, and an increase in the focusing of attention on the prey, which seems an important component in the regulation of the predatory pattern. Pharmacological evidence indicates that the VTA effect is mediated by the mesolimbic-mesocortical dopaminergic (DA) system.

Animals↗
PubMed1987

Inhibitory effect of the ventral tegmental A10 region on the hypothalamic defence reaction: evidence for a possible dopaminergic mediation.

The influence of A10 region neurons of the ventral tegmental area (VTA) on the defence reaction evoked by stimulation of the ventromedial hypothalamic nucleus (VMH) was studied in the cat. The latency of the hissing in the defence reaction increased when the VTA was stimulated both ipsi- and contralaterally. A sulpiride (50mg/kg i.p.) injection totally abolished the VTA-provoked increase of the hissing latency without affecting the basal response.

Animals↗
PubMed1986

Effects of substantia nigra stimulation on hypothalamic rage reaction in cats.

The effects of substantia nigra (SN) (pars compacta) stimulation on the rage reaction elicited by ventromedial hypothalamic nucleus (VMH) were investigated in the cat. The studied parameters of the rage reaction were: the current and the frequency threshold for the appearance of the hissing and the hissing latency. A facilitatory effect induced by the SN on the hypothalamic rage reaction was observed in the form of a decrease in the hypothalamic stimulus threshold for the hissing appearance and a decrease in the hissing latency. Moreover, when the VMH was stimulated with parameters below the threshold for the hissing display, simultaneous nigral activation determined its appearance. The excitatory influence exerted by the SN on the affective component of the aggressive behavior is discussed.

Aggression↗
PubMed1986

Stimulation of the ventral tegmental area (A10 region) enhances the hypothalamic attack behavior in the cat.

The influence of the A10 region of the ventral tegmental area (VTA) on the quiet biting attack evoked by stimulation of the lateral hypothalamic nucleus (LH) was studied. The latency of the biting was considered as reference value and measured with stop-watches; it remained constant when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of the A10 neuron group induced a facilitation of the aggression in the form of a decrease in the biting latency or a display of the attack pattern when LH was stimulated with parameters below the threshold for biting appearance. The facilitatory effect of the A10 neurons of the VTA is discussed.

Aggression↗
PubMed1985

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation, in the cat.

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.

Aggression↗
PubMed1985

The control exerted by the substantia nigra on the quiet biting attack elicited by hypothalamic stimulation in the cat.

The effects of substantia nigra (SN) (pars compacta) stimulation on the quiet biting attack evoked by hypothalamic activation in the cat were studied. The measure of the aggressive behavior was the latency of the biting which did not greatly change from one animal to another when hypothalamic stimulation was performed with the same parameters. Concurrent activation of the SN determined an inhibitory effect on the studied behavior in the form of an increase in the biting latency or loss of the attack pattern. The inhibitory role of the SN on predatory attack behavior is discussed.

Aggression↗
PubMed1984

[Effects of stimulation of the substantia nigra on the rage reaction evoked in the cat by hypothalamic stimulation].

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease of the hissing latency. The influence of the substantia nigra on the affective components of the aggressive behaviour in underlined.

Anger↗
PubMed1984

[An optoelectronic apparatus for the registration of stepping activity in small mammals].

In order to record the stepping activity in little size mammals, it was planned a set able to transform the stepping activity of the animals in electrical signals displayed on a polygraph. The set is formed by a complex transmitter-receiver, and transformer-recorder, that allow to record also high frequency stepping activity and its time variations.

Animals↗
PubMed1984

[Induced facilitation in the ventral tegmentum area on the latency of biting evoked by hypothalamic stimulation in the cat].

The effects of VTA stimulation on the quiet biting attack evoked by hypothalamic activation in the cat, were studied. The reference value of the aggressive behaviour was the latency of the biting. Concurrent activation of both the hypothalamus and VTA determined a decrease of the biting latency, which depended on the parameters of VTA stimuli. The facilitatory effect of the dopaminergic mesolimbic system on the attack behaviour is emphasized.

Aggression↗
PubMed1984

[The substantia nigra in quiet attack induced by hypothalamic stimulation in the cat].

The role of the substantia nigra on the quiet biting attack evoked by hypothalamic stimulation was investigated. Simultaneous activation of the hypothalamus and of the s. nigra determined a significant increase of the biting latency or in some case the disappearance of the attack pattern. The inhibitory role of the s. nigra on the quiet biting attack evoked by hypothalamic stimulation is discussed.

Aggression↗
PubMed1983

Modifications induced on the amygdaloid paroxysmal activity by entopeduncolar or nigral injection of kainic acid, in the cat.

Entopeduncolar or nigral injection of kainic acid determines an early decrease of the evoked amygdaloid paroxysmal activity and a later increase of the after discharge duration. This biphasic effect is likely due to the structural analogy of the drug with monosodium glutamate, a neuroexcitant amino acid. The data suggest that the basal ganglia exert a tonic control on the amygdaloid activity.

Amygdala↗