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Biomedical subjects

S Bigi

Publications and source records attributed to S Bigi.

7 recordsLinked to original sources
PubMed1994

Removal of the submaxillary salivary glands first increases and then abolishes the agonistic response of male mice in repeated social encounters.

Adult male mice of the CD-1 strain were sialectomized (bilateral removal of submaxillary salivary glands) under IP Nembutal anesthesia and then individually housed for 5 weeks. Control mice were sham operated. The behaviors of sialectomized and control mice towards untreated, intact, matched opponents were videotaped during the first 10 min of a 20-min social encounter repeated for 10 consecutive days (isolation days 36-46). On the first session, sialectomized mice exhibited significant increases in elements of aggression (attack, bite, offensive sideways, offensive upright, and tail rattling). These behavioral changes significantly decreased over the remaining encounters, while defensive behaviors (defensive upright, oblique, parry, and defensive sideways) and elements of arrested flight increased progressively. The results suggest that sialectomy, perhaps by removing salivary NGF, interferes with the coping response of mice towards repeated agonist challenge from a conspecific.

Adaptation, Psychological↗
PubMed1993

Neonatal capsaicin exposure affects isolation-induced aggressive behavior and hypothalamic substance P levels of adult male mice (Mus musculus).

Subcutaneous administration of capsaicin (50 mg/kg) at Postnatal Days 2 and 5 exerted long-term effects on isolation-induced aggressive behavior of adult mice (Mus musculus) of the CD-1 strain. Isolated capsaicin-treated mice (scored during a 10-min session) showed the highest frequency and the longest duration of total attacks, attacks, rattling, and offensive upright posture when compared with nonisolated capsaicin-treated subjects and both isolated and nonisolated vehicle control animals. Hypothalamic Substance P (SP) was assessed by radioimmunoassay. Capsaicin treatment significantly lowered hypothalamic SP content in both isolated and nonisolated mice. Moreover, individual scores of isolated capsaicin-treated subjects showed a significant correlation between SP depletion and expression of offensive upright posture. Isolation per se was revealed to play an important role in depleting SP from the hypothalamus.

Aggression↗
PubMed1993

Familiarity with conspecific odor and isolation-induced aggressive behavior in male mice (Mus domesticus).

Male Swiss CD-1 mice (Mus domesticus, n = 60) were isolated for 24 days. In the isolation group mice were exposed to their own odor; in the familiarity group mice were familiarized with pairmates' odor by daily exchange of bedding; and in the unfamiliarity group subjects (exposed) were familiarized with pairmates' odor, whereas the pairmates (nonexposed) were familiarized with odors of other isolated mice. Aggressive behavior was scored during 20-min sessions. Familiarity with the pairmate's odor (familiarity and exposed subgroups) caused an enhancement of aggressive behavior, shown by the highest frequency of tail rattling and offensive upright posture and by a decrease in latency to the 1st attack. Nonexposed subjects showed high values of submissive upright posture, screaming, fleeing, and freezing. The results suggest that dominantlike behavior, acquired in social isolation, may be directed toward a conspecific whose odor is familiar.

Aggression↗
PubMed1992

NGF decreases isolation-induced aggressive behavior, while increasing adrenal volume, in adult male mice.

Intravenous administration of highly purified murine nerve growth factor (NGF, either 15 or 30 micrograms/subject/day) for six consecutive days to adult male mice of the CD-1 strain markedly influenced a number of items of aggressive behavior induced by 5 weeks of individual housing. Control mice received the same doses of cytochrome c. During a 20-min fighting session on day 7, both NGF-treated groups showed longer Latency to the first Attack, while Total Attacking Time and Aggressive grooming were significantly lower when compared to control animals. Twenty-four h later, adrenals from the NGF- and cytochrome c-treated groups were dissected and analyzed by means of a Vidas Image-Analyzer. NGF administration produced a remarkable dose-dependent increase in both adrenal weight and volume (particularly in the medullary zone), supporting the hypothesis that adrenals represent a possible target for the NGF release from submaxillary salivary glands occurring upon intraspecific fighting.

Adrenal Glands↗
PubMed1991

Capsaicin affects aggressive behavior, but not hot plate responding, of adult male mice.

Adult male mice of albino Swiss-derived CD-1 strain were used to assess the effects of capsaicin (a powerful agent that produces a marked depletion of the undecapeptide substance P) on both intraspecific aggressive behavior (induced by 8 weeks of individual housing) and pain sensitivity. Capsaicin was given SC, 48 h before behavioral testing. Aggressive behavior, scored during a 5-min session under red light, was significantly enhanced by capsaicin treatment (50 or 100 microliters of a 7.5 mg/ml solution). In fact, Total Aggressive Episodes, Attacks, and Upright Offensive Posture were significantly higher in the two capsaicin-treated groups, while Latency to the first Attack was decreased, when compared to both vehicle or unhandled controls. A concomitant decrease in Submissive Postures and Flee was also evident in capsaicin mice. Hot plate testing (55 +/- 0.1 degrees C, cutoff time 30 s), carried out on nonisolated mice, did not reveal any difference among the two capsaicin groups (same doses) and vehicle or unhandled controls.

Aggression↗
PubMedDate not supplied

An updated role for nerve growth factor in neurobehavioural regulation of adult vertebrates.

Increasing attention has been focused on the role(s) of nerve growth factor (NGF) in neurobehavioural regulations of adult vertebrates. This interest springs from the emerging evidence that NGF is a "regulator" of physiological processes belonging to the three main homeostatic systems: the nervous, immune and endocrine systems. In fact, the spectrum of action of the NGF molecule is not restricted to neuronal cell types (central basal forebrain; peripheral sensory and sympathetic neurons) but extends also to nonneuronal cells. In mice intermale aggressive behaviour enhances serum NGF levels and promotes its synthesis in some hypothalamic areas. Other types of social events are able to cause NGF release, particularly under stress conditions. The achievement of a social role (dominant vs subordinate) is due to a functional loop involving salivary NGF release-->enhanced production of adrenal hormones-->submissive behaviour-->NGF release. In humans, plasma platelet-derived growth factor (PDGF) increases following mental stress. The aim of this review is to give an updated survey on NGF roles in neurobehavioural regulations of adult animals.

Animals↗