Differential modulation of the contextual conditioned emotional response by CB1 and TRPV1 receptors in the ventromedial prefrontal cortex: Possible involvement of NMDA/nitric oxide-related mechanisms.

Background: Blockade of cannabinoid CB1 or vanilloid TRPV1 receptors in the ventromedial prefrontal cortex of rats respectively increases or decreases the conditioned emotional response during re-exposure to a context previously paired with footshocks. Although these mechanisms are unknown, they may involve local modulation of glutamatergic and nitrergic signaling.

Aim: We investigated whether these mechanisms are involved in the reported effects of CB1 and TRPV1 modulation in the ventromedial prefrontal cortex.

Role of the endocannabinoid system in the dorsal hippocampus in the cardiovascular changes and delayed anxiety-like effect induced by acute restraint stress in rats.

Background: The dorsal hippocampus has a central role in modulating cardiovascular responses and behavioral adaptation to stress. The dorsal hippocampus also plays a key role in stress-associated mental disorders. The endocannabinoid system is widely expressed in the dorsal hippocampus and modulates defensive behaviors under stressful conditions.

The dorsolateral periaqueductal grey N-methyl-D-aspartate/nitric oxide/cyclic guanosine monophosphate pathway modulates the expression of contextual fear conditioning in rats.

The dorsolateral periaqueductal grey (dlPAG) plays an essential role in unconditioned fear responses and could also be involved in the expression of contextual fear responses. Activation of glutamate N-methyl-D-aspartate (NMDA) receptors and the nitric oxide (NO) pathway in this region facilitates anxiety-like responses. In the present study we investigated if antagonism of NMDA receptors or inhibition of the NO pathway in the dlPAG would attenuate behavioral and cardiovascular responses of rats submitted to a contextual fear-conditioning paradigm.

Mechanisms in the bed nucleus of the stria terminalis involved in control of autonomic and neuroendocrine functions: a review.

The bed nucleus of the stria terminalis (BNST) is a heterogeneous and complex limbic forebrain structure, which plays an important role in controlling autonomic, neuroendocrine and behavioral responses. The BNST is thought to serve as a key relay connecting limbic forebrain structures to hypothalamic and brainstem regions associated with autonomic and neuroendocrine functions. Its control of physiological and behavioral activity is mediated by local action of numerous neurotransmitters.

Inhibition of the NMDA receptor/Nitric Oxide pathway in the dorsolateral periaqueductal gray causes anxiolytic-like effects in rats submitted to the Vogel conflict test.

Background: Several studies had demonstrated the involvement of the dorsolateral portion of periaqueductal grey matter (dlPAG) in defensive responses. This region contains a significant number of neurons containing the enzyme nitric oxide synthase (NOS) and previous studies showed that non-selective NOS inhibition or glutamate NMDA-receptor antagonism in the dlPAG caused anxiolytic-like effects in the elevated plus maze.

Methods: In the present study we verified if the NMDA/NO pathway in the dlPAG would also involve in the behavioral suppression observed in rats submitted to the Vogel conflict test.