Biomedical subjects

G Crescimanno

Publications and source records attributed to G Crescimanno.

At least 19 recordsLinked to original sources

PubMed2000

Effects of sulpiride on the orienting movement evoked By acoustic stimulation in the Rat.

Drugs that selectively block D(2) receptors are known to provoke a rapid cell firing increase followed by A9 and A10 dopaminergic (DA) neuron inactivation (depolarization block). In this study, possible relationships between cell firing rapid increase and specific behavioral effects, linked to sensorimotor integration, were investigated in the rat. To this purpose, with the aid of a video camera apparatus and a frame-by-frame analysis, effects of sulpiride-induced blockade of DA D(2) receptors were analyzed on the orienting movement of the head induced by acoustic stimulation. In a control group of rats, during trials lasting 20 min, latency and duration of head turning (HT) were 186.15 +/- 51.66 ms and 266.87 +/- 47.49 ms, respectively. Sulpiride injection (20,40,100 mg/kg IP) provoked a dose-dependent increase of HT latency and duration; however, only latencies showed statistically significant variations. It is suggested that cell firing rapid increase, observed on A9 and A10 DA neurons, following sulpiride administration, may be correlated to rapid modifications of specific HT parameters linked to sensorimotor integration.

Acoustic Stimulation↗

PubMed1998

Effects of intraaccumbens microinjections of quinopirole on head turning and circling movement in the rat.

This study was designed to evaluate whether nucleus accumbens dopamine D2 receptors are involved in the initiation of the movement, as distinguished from its execution. For this purpose, the effects of the quinpirole-induced increase of nucleus accumbens dopamine D2 receptor activity were observed on specific parameters of the circling behavior and of its first stage, the head-turning (HT) movement. The experiments were performed on rats with unilateral 6-hydroxydopamine (6-OHDA) lesion of the pars compacta of the substantia nigra and d-amphetamine i.p. (3 mg/kg). Bilateral intraaccumbens microinjections of quinpirole (1, 5, and 10 microg/0.5 microl), an agonist of the D2 receptor family, were performed on three groups of animals. Bilateral saline (0.5 microl) was injected in a fourth group as control. An additional control experiment, with quinpirole (10 microg/0.5 microl) bilaterally injected in accumbens without d-amphetamine i.p., was also performed in a further group of 6-OHDA-lesioned animals. By means of a videoanalysis system, HT duration, angle, and speed were analyzed. Modifications of the circling rate (increase), HT duration (decrease), HT angle (decrease or increase according to the dose), and HT speed (increase) were observed. Moreover, a very close head-to-tail position and a very short-diameter type of turn were also evidenced. Similar modifications, even if different in amplitude and in % distribution, were observed following bilateral quinpirole in accumbens without d-amphetamine i.p. The results indicate a close relationship among head-turning speed, type of turn, and position of the animal in the circling motor sequence. We conclude that D2 receptor family in nucleus accumbens is involved in the initiation of movement as distinguished from its execution.

Animals↗

PubMed1998

Inhibitory effect of A10 dopaminergic neurons of the ventral tegmental area on the orienting response evoked by acoustic stimulation in the cat.

The effect of bilateral electric stimulation of A10 dopaminergic neurons of the ventral tegmental area (80-300 microA, 20-50 Hz, 0.1-0.5 ms, 2 s duration) on latency and duration of the orienting response, evoked by acoustic stimuli (4500-8000 Hz, 2 s), was studied in the cat. A10 neuron stimulation, simultaneous with the acoustic one, was performed with threshold parameters inducing minimal behavioral signs (head searching movement, sniffing, increase in alertness). By means of a videoanalysis system, a statistically significant increase, both of latency and duration of the response, was observed. The possible role of dopamine was studied administrating sulpiride (20 mg/kg i.p.), a dopaminergic antagonist prevalently acting on the mesolimbic-mesocortical system. In this condition, the disappearance of A10 neuron effect occurred. Sulpiride injection did not affect the parameters of the orienting response to acoustic stimulus alone, suggesting a direct effect on A10 dopaminergic neurons. Moreover, when saline administration was carried out, no significant modification of the effects, obtained following A10 neuron activation, was observed. The data suggest that A10 dopaminergic neurons, origin of the mesolimbic-mesocortical system, may be involved in the control of the response to sensory stimuli, likely by influencing sensorimotor integration processes. An involvement in the inhibitory regulation of the switching of attention is also discussed.

Acoustic Stimulation↗

PubMed1997

Effect of ageing on peak expiratory flow variability and nocturnal exacerbations in bronchial asthma.

The aim of this study was to evaluate the role of ageing on variability of airflow obstruction and on the specific pattern of nocturnal exacerbations ("morning dipping" of peak expiratory flow (PEF)) in asthma. Two groups of stable asthmatics (Group A: 23 patients, aged 14-47 yrs; Group B: 20 patients, aged 53-74 yrs), that were similar for duration of disease, degree of obstruction and response to bronchodilators, were studied. PEF was monitored four times daily for 2 weeks, and amplitude of variation and "morning dip" were calculated. Both PEF amplitude and "morning dip" were greater in the older patients (p<0.005). Amplitude was negatively correlated with baseline forced expiratory volume in one second (FEV1) in both groups (p<0.01); multiple correlation with age, duration of disease, baseline FEV1 and degree of reversibility was significant in the older group only. Morning dip was inversely correlated to baseline FEV1 (p<0.01) and reversibility (p<0.05). Nocturnal symptoms were reported by all of the five Group A "dippers", but by only 6 of the 13 Group B "dippers" (p<0.04). Ageing contributes to increased variability of airway calibre in asthma. Aged patients are potentially at risk because functional evidence of nocturnal asthma may frequently be accompanied by a poor subjective awareness. Therefore, a more extensive practice of PEF monitoring is recommended in aged asthmatics.

Adolescent↗

PubMed1995

Modifications of head turning and circling movement following sulpiride microinjections into nucleus accumbens in the rat.

The aim of this study was to determine whether a relationship exists between nucleus accumbens D2 receptors, circling behavior, and its first stage, the head turning. Rats were unilaterally lesioned in the substantia nigra with 6-hydroxydopamine and afterward treated with d-amphetamine IP following bilateral intraaccumbens microinjections (1, 5, 10 micrograms/0.5 microliters) of sulpiride, a D2 receptor antagonist. Computer-assisted video analysis allowed the study of some parameters (number of turns, type of turn, head turning duration, degree and speed) characterizing rotatory activity. Sulpiride microinfusion resulted in a dose-dependent decrease of the number of turns and head rotation speed and in a dose-dependent increase of head-turning duration. Two turn types were observed in relation to the animal's position: a large head-to-tail position with a short-diameter turn type following sulpiride microinjection, and a close head-to-tail position in relation to a wide diameter turn type in the control condition (saline). The results show a relationship between head turning parameters, circling behavior, and D2 receptors in nucleus accumbens, which may be also involved in the regulation of some mechanisms related to sensory-motor integration in the rat.

Animals↗

PubMed1994

Accumbens microinjection of LY 171555 and sulpiride: effects on circling behaviour, in the rat.

In rats with unilateral 6-hydroxydopamine lesions of the substantia nigra (pars compacta) and amphetamine i.p. some parameters of the rotational activity, following intra-accumbens microinjection of D2 agonist (LY 171555) and antagonist (sulpiride), have been analyzed. An increase in the number of turns was observed with LY 171555, whereas sulpiride determined a decrease. The type of circling was also analyzed: D2 agonist induced a very close turn around the central axis of the animal and D2 antagonist a close turn in the centre of the cage. Data were compared with control condition, which exhibited a large turn around the walls of the cage. The results show that pharmacological manipulation of nucleus accumbens influences rotational behaviour with a specific role for D2 receptors.

Amphetamine↗

PubMed1993

Influence of ventral tegmental area (A10 region) on flight behaviour elicited by hypothalamic stimulation in the cat.

The influence of the ventral tegmental area (VTA) (dopaminergic A10 group neurons) on flight behaviour, induced by hypothalamic stimulation, was studied in the cat. Co-stimulation of hypothalamus and VTA (ipsi- or contralateral) induced an increase of the flight latency. Slow-motion analysis of flight behaviour showed that this increase was due to the augmentation of the fixation latency (FL) whereas the upright latency (UL) was not modified. Sulpiride injection (50 mg/kg i.p.) provoked the disappearance of VTA effect without affecting the basal behavioural sequence. The results show that DA A10 group neurons increase the attentive component of the flight reaction, suggesting a possible influence of the DA A10 system on the mechanisms modulating focused attention in the animal.

Anesthesia↗

PubMed1992

The effect of age on mitogen responsive T cell precursors in human beings is completely restored by interleukin-2.

It is well known that the function of T lymphocytes is significantly impaired by advancing age. In the present study, attempts have been made to further characterize the T cell impairment of elderly subjects. Thus, we have performed limiting dilution microculture analysis to evaluate the precursor frequency of T lymphocytes responding to a mitogenic stimulus in old and young subjects. Furthermore we have evaluated the activity of recombinant interleukin-2 (rIL-2) on these cells. The results demonstrate that in older subjects the frequency of these precursors is significantly decreased. The in vitro treatment with rIL-2 increased the frequency of mitogen responsive T lymphocyte precursors in both groups so that the difference between the two groups was not significant. Thus present results extend the findings demonstrating that older subjects display an impairment of T cell functions and that IL-2 treatment may correct these alterations. In particular, they confirm the hypothesis that age-associated functional changes are more likely due to diminished numbers of reactive cells, than to a decline in the activity of all cells.

Adult↗

PubMed1992

Blood antiphospholipid antibody levels are influenced by age, sex and HLA-B8,DR3 phenotype.

Antiphospholipid antibodies (APA) are known to be associated with a number of seemingly heterogeneous pathological conditions that are part of the antiphospholipid syndrome, formerly called anticardiolipin syndrome. Recent studies on the mechanism of action of these autoantibodies suggest that we are dealing with a new autoimmune syndrome which may occur either in a primary form or in the context of other autoimmune diseases, mainly systemic lupus erythematosus (SLE). Moreover, increased levels of APA have been found in elderly subjects, who are known to display increased frequency of autoimmune phenomena. It is well known that many autoimmune diseases, including SLE, are associated with HLA antigens, particularly with HLA-B8,DR3 phenotype. In our study, APA serum levels were analyzed in 26 old subjects and in 56 young ones. The results demonstrate that HLA-B8,DR3-positive young females display significantly higher levels of APA than HLA-B8,DR3-negative ones. Interestingly, the same is true for elderly subjects on the whole with respect to young individuals. These data are consistent with previous findings demonstrating that HLA-B8,DR3-positive subjects (mainly female) as well as old subjects display (also in the absence of any clinical manifestation), multiple immune dysfunctions that may underlie the predisposition to autoimmunity.

Adult↗

PubMed1991

Soluble interleukin-2 receptor release defect in vitro in elderly subjects.

The evidence from several studies indicates that as individuals age, they may display immune dysfunctions, mostly T cell dysfunctions. Recently, a soluble form of the receptor for interleukin-2 (IL-2) (sIL-2R) has been demonstrated in human sera and in vitro stimulated culture supernatants from human T lymphocytes. In the present paper, we report in vitro sIL-2R production from peripheral blood mononuclear cells in elderly subjects. The results show that no difference exists for unstimulated cultures, whereas after mitogen stimulation the elderly subjects showed the lowest values compared with young ones. These findings suggest that sIL-2R may provide a new tool for the study of T lymphocyte dysfunctions in old age.

Aged↗

PubMed1991

The role of the claustrum in the bilateral control of frontal oculomotor neurons in the cat.

The effect of claustrum (CL) stimulation on the spontaneous unitary activity of ipsi and contralateral frontal oculomotor neurons, was studied in chloralose-anaesthetized cats. A total of 205 units was bilaterally recorded in the medial oculomotor area, homologous of the primate "frontal eye fields"; 127 neurons were identified as projecting to the superior colliculus; for 33 of these last units stimulation of the ipsilateral CL provoked an excitatory effect lasting 10-25 ms and appearing with a latency of 5-15 ms; on 8 units the excitatory effect was followed by an inhibition lasting 100-250 ms. Ninety-eight of the 127 neurons were also tested through activation of the contralateral CL: 13 cells showed an excitatory effect lasting 10-35 ms and appearing with a latency of 20-50 ms. In three of the thirteen units the excitatory effect was followed by an inhibition lasting 100-150 ms. Complete section of the corpus callosum abolished the contralateral CL effect, suggesting the existence of a direct claustro-contralateral oculomotor cortex pathway running through the corpus callosum. The results could support the hypothesis that the CL may play a role in the bilateral control of the visuomotor performance.

Animals↗

PubMed1990

Effect of claustrum stimulation on neurons of the contralateral medial oculomotor area, in the cat.

In chloralose-anaesthetized cats, the extracellular spontaneous unitary activity was recorded from 157 neurons, located in the medial oculomotor area. 98 units were identified as projecting onto the superior colliculus. Electrical stimulations of the contralateral claustrum provoked, on 13 of these cells, an excitatory effect, lasting 10-35 ms and appearing with a latency of 20-50 ms. Full length section of the corpus callosum totally abolished the contralateral claustrum effect. The results suggest that in the cat, the claustrum may have a role in the bilateral control of the visuo-motor performance.

Animals↗

PubMed1989

Effect of claustrum activation on the spontaneous unitary activity of frontal eye field neurons in the cat.

The influence of claustrum stimulation on spontaneous unitary activity of the ipsilateral frontal oculomotor area was analyzed in anesthetized cats. Sixty-five neurons were isolated, 37 of which (57%) were identified as projecting to the superior colliculus; on 12 of these last units (32%), electrical activation of the dorsal claustrum provoked an excitatory effect, which appeared after a latency of 5-15 ms and lasted 10-25 ms. These data could suggest the involvement of the claustrum in the visuomotor coordination function.

Action Potentials↗

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↗

PubMed1989

Claustral influence on ipsi- and contralateral motor cortical areas, in the cat.

The electrophysiological relationships between the claustrum and the contralateral motor areas of the cerebral cortex were studied in anaesthetized cats. The extracellular unitary activity of 207 pyramidal tract neurons (PTNs) was recorded from area 4 (125 cells) and area 6 (82 cells). Single shock activation of the contralateral claustrum affected 26% of the total tested PTNs, causing long lasting inhibition (44 PTNs) or long lasting inhibition preceded by early excitation (10 PTNs). Forty-three neurons of the 54 were also influenced by ipsilateral claustrum stimulation. Surgical removal of motor and insular cortices ipsilateral to the stimulated claustrum did not modify claustrum inhibition on contralateral PTNs, whereas section of the corpus callosum abolished this effect, suggesting the existence of a direct claustro-contralateral motor cortex pathway passing through the corpus callosum. These results support the hypothesis that the claustrum may exert a bilateral control on motor coordination.

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↗