The brain decade in debate: III. Neurobiology of emotion.

This article is a transcription of an electronic symposium in which active researchers were invited by the Brazilian Society of Neuroscience and Behavior (SBNeC) to discuss the advances of the last decade in the neurobiology of emotion. Four basic questions were debated: 1) What are the most critical issues/questions in the neurobiology of emotion? 2) What do we know for certain about brain processes involved in emotion and what is controversial? 3) What kinds of research are needed to resolve these controversial issues? 4) What is the relationship between learning, memory and emotion? The focus was on the existence of different neural systems for different emotions and the nature of the neural coding for the emotional states. Is emotion the result of the interaction of different brain regions such as the amygdala, the nucleus accumbens, or the periaqueductal gray matter or is it an emergent property of the whole brain neural network? The relationship between unlearned and learned emotions was also discussed.

The brain decade in debate: II. Panic or anxiety? From animal models to a neurobiological basis.

This article is a transcription of an electronic symposium sponsored by the Brazilian Society of Neuroscience and Behavior (SBNeC). Invited researchers from the European Union, North America and Brazil discussed two issues on anxiety, namely whether panic is a very intense anxiety or something else, and what aspects of clinical anxiety are reproduced by animal models. Concerning the first issue, most participants agreed that generalized anxiety and panic disorder are different on the basis of clinical manifestations, drug response and animal models.

Behavioral effects in the elevated plus maze of an NMDA antagonist injected into the dorsal hippocampus: influence of restraint stress.

The objective of the study was to investigate the influence of restraint stress on the effects of 2-amino-7-phosphonoheptanoic acid (AP7), an NMDA receptor antagonist, injected into the hippocampus of rats submitted to the elevated plus maze (EPM). Male Wistar rats with cannulas aimed to the dorsal hippocampus were forced immobilized for 2 h. Twenty four hours later they received bilateral injections of saline or AP7 (10 nmol/0.

Anxiolytic effect of a CRH receptor antagonist in the dorsal periaqueductal gray.

Corticotropin-releasing hormone (CRH) is anxiogenic when microinjected into the dorsal periaqueductal gray (DPAG). Microinjection of alpha-helical-CRH9-41 (0.5 microgram), a CRH receptor antagonist, however, failed to change anxiety levels.

Expression of neuronal nitric oxide synthase mRNA in stress-related brain areas after restraint in rats.

The objective of the present study was to investigate the expression of neuronal nitric oxide synthase (nNOS) mRNA in stress-related areas after restraint. Male Wistar rats (n=4-6/group) submitted to 2 h of restraint during one (acute) or seven (chronic) days were sacrificed 24 h after the last restraint period. In situ hybridisation was performed with oligonucleotide probes radiolabeled with (35)S.

The hemolytic component of cancer anemia: effects of osmotic and metabolic stress on the erythrocytes of rats bearing multifocal inoculations of the Walker 256 tumor.

Cancer anemia is classified as an anemia of chronic diseases, although it is sometimes the first symptom of cancer. Cancer anemia includes a hemolytic component, important in the terminal stage when even transfused cells are rapidly destroyed. The presence of a chronic component and the terminal complications of the illness limit studies of the hemolytic component.

Behavioral effects of intra-nigral microinjections of manganese chloride: interaction with nitric oxide.

1. Microinjection of manganese chloride (MnCl2) into the rat substantia nigra pars compacta (SNc) induces a neurodegenerative process manifested by apomorphine-induced rotational behavior. Manganese intoxication produces a parkinsonism-like phenotype in humans.

Effects of tryptophan depletion on anxiety induced by simulated public speaking.

Several lines of evidence point to the participation of serotonin (5HT) in anxiety. Its specific role, however, remains obscure. The objective of the present study was to evaluate the effect of reducing 5HT-neurotransmission through an acute tryptophan depletion on anxiety induced by a simulated public speaking (SPS) test.

Induction of Fos protein immunoreactivity by spinal cord contusion.

The objective of the present study was to identify neurons in the central nervous system that respond to spinal contusion injury in the rat by monitoring the expression of the nuclear protein encoded by the c-fos gene, an activity-dependent gene, in spinal cord and brainstem regions. Rats were anesthetized with urethane and the injury was produced by dropping a 5-g weight from 20.0 cm onto the exposed dura at the T10-L1 vertebral level (contusion group).

Modulation of carbachol-induced antinociception from the rat periaqueductal gray.

The tail-flick latency (TFL) and the vocalisation test (VT) thresholds were all increased by microinjecting CCh into the dorsal periaqueductal gray (dPAG) of rats. The effects on the TFL were mimicked by dimethyl-phenylpiperazinium, and inhibited by local mecamylamine or intraperitoneal (i.p.

Behavioral and c-fos expression changes induced by nitric oxide donors microinjected into the dorsal periaqueductal gray.

The dorsolateral periaqueductal gray matter (DLPAG) is a key structure in behavioral and autonomic expression of defensive reactions. Inhibitors of nitric oxide (NO) synthase microinjected into the DLPAG are anxiolytic. The purpose of the present study was to evaluate the behavioral effects produced by administration of two NO donors, SIN-1 or DEA/NO, into the DLPAG.

Sub-chronic inhibition of nitric-oxide synthesis modifies haloperidol-induced catalepsy and the number of NADPH-diaphorase neurons in mice.

Rationale: NG-nitro-L-arginine (L-NOARG), an inhibitor of nitric-oxide synthase (NOS), induces catalepsy in mice. This effect undergoes rapid tolerance, showing a significant decrease after 2 days of sub-chronic L-NOARG treatment. Nitric oxide (NO) has been shown to influence dopaminergic neurotransmission in the striatum.

Restraint-induced hypoactivity in an elevated plus-maze.

Rodents submitted to restraint stress show decreased activity in an elevated plus-maze (EPM) 24 h later. The objective of the present study was to determine if a certain amount of time is needed after stress for the development of these changes. We also wanted to verify if behavioral tolerance of repeated daily restraint would be detectable in this model.

Defense reaction induced by a metabotropic glutamate receptor agonist microinjected into the dorsal periaqueductal gray of rats.

The behavioral effects of trans-(+/-)-1-amino-1, 3-cyclopentanedicarboxylic acid (t-ACPD), a metabotropic glutamate receptor (mGluR) agonist, or 0.9% (w/v) saline, injected into the dorsal periaqueductal gray (DPAG), was investigated. Male Wistar rats showed defense reactions characterized by jumps toward the top edges of the cages (saline = 0 vs t-ACPD = 6.

Anxiolytic effect of methylene blue microinjected into the dorsal periaqueductal gray matter.

The dorsal periaqueductal gray (DPAG) has been implicated in the behavioral and autonomic expression of defensive reactions. Several results suggest that, along with GABA, glutamate and serotonin, nitric oxide (NO) may play a role in defense reactions mediated by this region. To further investigate this possibility we microinjected methylene blue (MB; 10, 30 or 100 nmol/0.

Serotonin modulation of catalepsy induced by N(G)-nitro-L-arginine in mice.

N(G)-(Nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide synthase, induces catalepsy in mice. The objective of the present work was to investigate if serotonergic drugs are able to modulate this effect. Results showed that the cataleptogenic effect of L-NOARG (40 mg/kg) in male albino-Swiss mice was enhanced by pre-treatment with (+)-N-tert-butyl-3-(4-[2-methoxyphenyl]piperazin-1-yl)-2-phenylpro panamide ((+)-WAY-100135, 5 or 10 mg/kg), a 5-HT1A-selective receptor antagonist, and by ketanserin (5 or 10 mg/kg), a 5-HT2A receptor and alpha1-adrenoceptor antagonist.

Comparison of buspirone with diazepam and fluvoxamine on aversive classical conditioning in humans.

The effects of buspirone, fluvoxamine and diazepam were investigated, using healthy volunteers, in an aversive conditioning paradigm, a putative model for conditioned anxiety. The main prediction was that buspirone, an anxiolytic agent which reduces activity in serotonin (5-hydroxytryptophan, 5-HT) neurones, would attenuate aversively conditioned skin conductance responses. Skin conductance responses were recorded to 10 neutral tones (habituation phase).

The influence of septal lesions on sodium and water retention induced by Walker 256 tumor.

In the course of studies on the effects of septal area lesions on neuroimmunomodulation and Walker 256 tumor development, it was observed that tumor-induced sodium and water retention was less marked in lesioned than in non-lesioned rats. In the present study possible mechanisms involved in this phenomenon were investigated. The experiments were performed in septal-lesioned (LW; N = 15) and sham-operated (SW; N = 7) 8-week-old male Wistar rats, which received multifocal simultaneous subcutaneous (sc) inoculations of Walker 256 tumor cells about 30 days after the stereotaxic surgery.

Molecular characterization and crystallization of Diocleinae lectins.

Molecular characterization of seven Diocleinae lectins was assessed by sequence analysis, determination of molecular masses by mass spectrometry, and analytical ultracentrifugation equilibrium sedimentation. The lectins show distinct pH-dependent dimer-tetramer equilibria, which we hypothesize are due to small primary structure differences at key positions. Lectins from Dioclea guianensis, Dioclea virgata, and Cratylia floribunda seeds have been crystallized and preliminary X-ray diffraction analyses are reported.

Reduced exploratory activity of audiogenic seizures susceptible Wistar rats.

Patients with epilepsy and animals with experimental usually show behavioral changes such as increased anxiety. Audiogenic seizures (AS) are a model of generalized tonic-clonic limbic seizures induced by sound stimulation in genetically susceptible animals. The objective of this paper was to evaluate the exploratory activity of an inbred strain derived from Wistar progenitors that has been selected in our laboratory for AS susceptibility.

Eyelid changes in long-standing leprosy.

To describe eyelid changes in ocular leprosy, 74 patients (148 eyes or 296 eyelids) were examined, focusing on eyelid abnormalities. The adnexal examination included evaluation of the upper eyelid crease pattern, qualitative assessment of the orbicularis oculi muscle function, measurement of the distance between the corneal reflex and the upper eyelid margin (margin reflex distance), and slit-lamp biomicroscopy of the eyelashes and tarsal conjunctiva. Eyelash ptosis was a common finding associated with a multiple upper eyelid crease pattern and trichiasis.

Differential expression of c-fos mRNA and Fos protein in the rat brain after restraint stress or pentylenetetrazol-induced seizures.

1. c-fos mRNA expression and Fos protein expression were investigated by in situ hybridization and immunohistochemistry after 30 min of forced restraint stress or pentylenetetrazol (PTZ; 64 mg/kg, i.p.

Intra-hippocampal administration of cycloheximide attenuates the restraint-induced exploratory deficit of an elevated plus maze.

Rats submitted to 2 h of restraint stress show a reduced open arm exploration in the elevated plus maze 24 h later. The stress-induced exploratory deficit is prevented by i.c.

Catalepsy induced by nitric oxide synthase inhibitors.

1. Previous study showed that N(G)-nitro-L-arginine (L-NOARG), an inhibitor of nitric bxide synthase, induces catalepsy in a dose-dependent manner in male albino-Swiss mice. 2.

Anxiogenic effect of corticotropin-releasing hormone in the dorsal periaqueductal grey.

To investigate whether the dorsal periaqueductal grey (DPAG) might be involved in the anxiogenic effect of intracerebroventricular (i.c.v.