Biomedical subjects

F Cirulli

Publications and source records attributed to F Cirulli.

26 records · Page 2Linked to original sources

PubMed1996

NGF regulatory role in stress and coping of rodents and humans.

Nerve growth factor (NGF) is a polypeptide growth factor which exerts trophic and differentiative effects on specific peripheral and central populations of neurons. Recent data showing that various cellular types of the endocrine and immune systems are able to synthesize and release NGF have suggested that this neurotrophic factor may also play an important role in vertebrate physiologic homeostasis. Previous studies using a mouse model of aggressive behavior have shown that NGF levels increase in both plasma and the CNS following intermale agonistic encounters. More recently, we have extended this research area to include other species: in particular, humans. The data now available indicate that labour and lactation, or the occurrence of a stressful event such as the very first jump with a parachute causes in NGF plasma levels as well as changes in the distribution of NGF receptors on lymphocytes. This review aimed to outline the current understanding of NGF role in vertebrates in stress-related events.

Adaptation, Psychological↗

PubMed1996

Affiliation in periadolescent rats: behavioral and corticosterone response to social reunion with familiar or unfamiliar partners.

The aim of this study was to investigate whether the social relationship between periadolescent rats, which is characterized by a high expression of play behavior, resembles attachment or whether it reflects a nonspecific social attraction between peers. Sprague-Dawley rats have been kept in pairs with a conspecific of the same age and sex from the time of weaning (PND 21). On PND 34, the members of each pair were separated for a 24-h period and randomly assigned to one of three groups: a) immediately sacrificed (NT = nontreated); b) reunited for 30 min with their previous cagemate (FAM); or c) with an unfamiliar conspecific of the same age and sex (UNF). During the reunion, the occurrence of both social and nonsocial behaviors was scored. Overall, periadolescent UNF animals spent more time in social investigation than FAM rats, which were conversely more involved in cage-oriented activities. In addition, higher levels of rough-and-tumble play were expressed in encounters between UNF subjects than between FAM rats. Finally, within the female group, UNF rats were more involved in play soliciting and less in digging activity than FAM animals. Blood corticosterone levels, which were measured at the end of the separation period, were higher in females than in males and were significantly lower than following reunion in a novel environment. The degree of familiarity did not affect hormonal changes. Results suggest that periadolescent rats do not form attachment relationships with each other. However, partner familiarity appears to be an important variable affecting social relationships.

Aging↗

PubMed1996

Haloperidol treatment decreases nerve growth factor levels in the hypothalamus of adult mice.

1. In a first study different doses of haloperidol (0.6, 1.2, 2.5, 5, 10, or 20 mg/kg; intraperitoneally) were administered to adult male mice (CD-1 strain) and tested for their ability to induce catalepsy. 2. The minimal haloperidol dose inducing complete catalepsy was found to be the 10 mg/kg dose and selected for the second experiment. 3. Using an immunoenzymatic assay (ELISA) hypothalamic nerve growth factor (NGF) level was measured 20 or 180 min following haloperidol injection (10 mg/kg). 4. Haloperidol treatment decreased NGF levels in mouse hypothalamus and this effect did not differ at the two time points tested. 5. The role of hypothalamic NGF in stress-related events is discussed.

Animals↗

PubMed1994

Differential influence of corticosterone and dexamethasone on schedule-induced polydipsia in adrenalectomized rats.

Previous studies have shown that adrenalectomy prevents the normal acquisition of schedule-induced polydipsia (SIP), while corticosterone (CORT) administration reinstates this behavior in adrenalectomized (ADX) rats. These studies investigated which corticosteroid receptor is responsible for mediating CORT effects on SIP. In Experiment I the effects of dexamethasone (DEX) and CORT on the acquisition of SIP were studied. DEX and CORT pellets (respectively 15 mg and 200 mg) were implanted subcutaneously in ADX rats. CORT but not DEX replacement was able to reinstate SIP in ADX rats. Because DEX binds almost exclusively to glucocorticoid receptors (GRs), while CORT binds to both GRs and mineralocorticoid receptors (MRs), results from Experiment I indicated that occupancy of GRs alone is not sufficient for SIP acquisition. In Experiment II CORT pellets of different concentrations (1, 10, 50, 200 mg) were implanted in ADX rats in order to determine whether MRs alone, or a combination of GRs and MRs are required for SIP reinstatement. Results from Experiment II showed that the 1 and 10 mg CORT pellets were not able to reinstate SIP in adrenalectomized rats, while animals implanted with 50 or 200 mg pellets did exhibit the behavior. These results indicate that occupancy of both MRs and GRs is required for SIP acquisition.

Adrenal Glands↗

PubMed1994

Behavioral and hormonal responses to stress in the newborn mouse: effects of maternal deprivation and chlordiazepoxide.

These studies investigated behavioral and hormonal responses to stress in developing mice. Experiment 1 examined the effects of 24-hr maternal deprivation on corticosterone (CORT) secretion and ultrasonic vocalization (UVZ) rate in 4-, 8-, and 12-day-old mice. At these ages, exposure to a novel environment resulted in minimal changes in CORT secretion. Maternal deprivation increased pups' CORT secretion in an age-dependent fashion but did not affect their UVZ rate. The aim of experiment 2 was to test the effects of chlordiazepoxide (CDP), an anxiolytic compound, on CORT secretion and UVZ in both normally reared and in maternally deprived 8-day-old mice. CDP administration elevated CORT secretion in a dose-dependent fashion, producing larger CORT increases in deprived (DEP) animals. CDP affected UVZ only in nondeprived (NDEP) animals: UVZ rate was decreased by high CDP doses. Overall, these findings demonstrate that the infant mouse shows a period of stress hyporesponsiveness similar to the rat and that maternal presence contributes to inhibit adrenocortical activity. CDP administration, but not novelty exposure, increased CORT secretion in 8-day-old normally reared mice suggesting that during the stress hyporesponsive period, the HPA axis is capable of responding only to specific stimuli. Changes in HPA axis activity and UVZ rate resulting from maternal deprivation and/or CDP challenge do not seem to be directly related.

Animals↗

PubMed1994

Effects of repeated administrations of EGF and TGF-alpha on mouse neurobehavioral development.

In this study we tested the effects of repeated administrations of Epidermal Growth Factor (EGF) and Transforming Growth Factor-alpha (TGF-alpha) on mouse pups' neurobehavioral development. Each subject was injected subcutaneously with either EGF or TGF-alpha on postnatal days 2, 4, 6, 8, and 10. Pups treated with these two peptides showed accelerated eyelid opening and eruption of the lower incisors when compared to Cytochrome c-injected control littermates. EGF, but not TGF-alpha, resulted in a slight body growth retardation. When scored for a number of neurobehavioral parameters, EGF pups showed a delayed appearance of the righting reflex. Also, EGF-treated pups exhibited greater ultrasonic vocalization calling rates than controls when tested on postnatal day 7. Overall, TGF-alpha administration resulted in minor effects, when compared with EGF treatment, probably as a result of the lower dose administered (EGF: 3.5 mg/kg vs TGF-alpha: 1 mg/kg). TGF-alpha affected pups' eyelid opening and incisor eruption, similarly to EGF, but seemed to exert an opposite effect on some neurobehavioral scores, in line with what was already reported for Nerve Growth Factor (NGF) (Calamandrei and Alleva, 1989). These results confirm the role played by polypeptide growth factors on mammalian physical and neurobehavioral development and suggest that TGF-alpha might affect mouse brain development in a similar fashion as NGF.

Animals↗

PubMedDate not supplied

Early disruption of the mother-infant relationship: effects on brain plasticity and implications for psychopathology.

Early environmental manipulations can impact on the developing nervous system, contributing to shape individual differences in physiological and behavioral responses to environmental challenges. In particular, it has been shown that disruptions in the mother-infant relationship result in neuroendocrine, neurochemical and behavioural changes in the adult organism, although the basic mechanisms underlying such changes have not been completely elucidated. Recent data suggest that neurotrophins might be among the mediators capable of transducing the effects of external manipulations on brain development. Nerve growth factor and brain-derived neurotrophic factor are known to play a major role during brain development, while in the adult animal they are mainly responsible for the maintenance of neuronal function and structural integrity. Changes in the levels of neurotrophic factors during critical developmental stages might result in long-term changes in neuronal plasticity and lead to increased vulnerability to aging and to psychopathology.

Aging↗

PubMedDate not supplied

Long-term effects of acute perinatal asphyxia on rat maternal behavior.

In this study we used a rat model of graded perinatal asphyxia to study the long-term consequences of this manipulation on rat maternal behavior at adulthood. Rats were delivered by cesarean (C) section and the pups, still in the uterus horns, were placed into a water bath at 37 degrees C for periods of 0 (controls) or 20 min (asphyxia). Subsequently, female pups were given to surrogate mothers, weaned at 21 days postnatally and then left undisturbed until adulthood, when they were mated. Once they gave birth, on postnatal days (Pnds) 1, 3, 5, 7, 9, 11 and 13 they were observed in the home cage five times per day to assess their maternal behavior in an undisturbed condition. In addition, maternal behavior was observed for 30 min in a novel cage on Pnds 4 and 8. Perinatal asphyxia affected maternal behavior in the home cage, hypoxic females being more often found outside the nest area and performing more often behaviors such as self-grooming. Principal component analysis confirmed a more 'active' behavioral profile for hypoxic females. Hypoxic mothers were characterized by a longer latency to perform on-nest behavior and by a reduced frequency of pup retrieval and licking in the novel cage. No significant differences in corticosterone secretion in response to an acute stressor were found in dams belonging to the different treatments or in the body weights of the offspring. These results are suggestive of an arousal deficit due to perinatal hypoxia and point to the dopaminergic system as a potential neurochemical target for an early hypoxic insult.

Age Factors↗