Prepulse inhibition of the acoustic startle reflex impairment by 5-HT2A receptor activation in the inferior colliculus is prevented by GABAA receptor blockade in the pedunculopontine tegmental nucleus.

The relationship between serotonin dysfunction and schizophrenia commenced with the discovery of the effects of lysergic acid diethylamide (LSD) that has high affinity for 5-HT receptors. Activation of these receptors produces perceptual and behavioural changes such as illusions, visual hallucinations and locomotor hyperactivity. Using prepulse inhibition (PPI) of the acoustic startle, which is impaired in schizophrenia,we aimed to investigate:i) the existence of a direct and potentially inhibitory neural pathway between the inferior colliculus (IC) and the pedunculopontine tegmental nucleus (PPTg) involved in the mediation of PPI responses by a neural tract tracing procedure;ii) if the microinjection of the 5-HT receptors agonist DOI in IC would activate neurons in this structure and in the PPTg by a c-Fos protein immunohistochemistry study;iii) whether the deficits in PPI responses, observed after the administration of DOI in the IC, could be prevented by the concomitant microinjection of the GABA receptor antagonist bicuculline in the PPTg.

Clozapine prevented social interaction deficits and reduced c-Fos immunoreactivity expression in several brain areas of rats exposed to acute restraint stress.

In the present study, we evaluate the effect of acute restraint stress (15 min) of male Wistar rats on social interaction measurements and c-Fos immunoreactivity (c-Fos-ir) expression, a marker of neuronal activity, in areas involved with the modulation of acute physical restraint in rats, i.e., the paraventricular nucleus of the hypothalamus (PVN), median raphe nucleus (MnR), medial prefrontal cortex (mPFC), cingulate prefrontal cortex (cPFC), nucleus accumbens (NaC), hippocampus (CA3), lateral septum (LS) and medial amygdala (MeA).

Repeated crack cocaine administration alters panic-related responses and delta FosB immunoreactivity in panic-modulating brain regions.

Crack cocaine is the crystal form of cocaine, produced by adding sodium bicarbonate to cocaine base paste. Brazil is the largest consumer of crack cocaine in the world. Users of crack cocaine show important physiological and behavioral alterations, including neuropsychiatric symptoms, such as anxiety-related symptoms.

Chronic corticosterone increases ΔFOSB and CRFR1 immunoreactivity in brain regions that modulate aversive conditioning.

Previous studies showed that chronic treatment with corticosterone facilitates elevated T-maze (ETM) inhibitory avoidance and a step-down avoidance task, responses that have been used to investigate aversive conditioning and memory processes. On the other hand, chronic corticosterone does not alter ETM escape from the open arms. The purpose of the present study was to further investigate the effects of chronic corticosterone treatment (200 mg pellets, 21-day release) in an animal model of anxiety that does not involve aversive conditioning: the light/dark transition model.

Lactulose decreases neuronal activation and attenuates motor behavioral deficits in hyperammonemic rats.

Lactulose is a nonabsorbable disaccharide commonly used in clinical practice to treat hepatic encephalopathy. However, its effects on neuropsychiatric disorders and motor behavior have not been fully elucidated. Male Wistar rats were bile-duct ligated, and 3 weeks after surgery, treated with lactulose administrated by gavage (1.