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Panic disorder: is the PAG involved?

Del-Ben CM, Graeff FG - Neural Plast. (2009)

Bottom Line: Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients.There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients.Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.

View Article: PubMed Central - PubMed

Affiliation: Psychiatry Division, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes, 3900, 14048-900 Ribeirão Preto, SP, Brazil. delben@fmrp.usp.br

ABSTRACT
Data from studies with humans have suggested that abnormalities of midbrain structures, including the periaqueductal gray matter (PAG), could be involved in the neurobiology of panic disorder (PD). The electrical stimulation of the PAG in neurosurgical patients induces panic-like symptoms and the effect of drugs that are effective in the treatment of PD in the simulation of public speaking model of anxiety is in agreement with data from animal models of PD. Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients. There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients. Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.

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Related in: MedlinePlus

Schematicrepresentation of the dual role of serotonin on fear and anxiety, according toDeakin and Graeff theory.
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Related In: Results  -  Collection


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fig1: Schematicrepresentation of the dual role of serotonin on fear and anxiety, according toDeakin and Graeff theory.

Mentions: More recently, Lowry etal. [15] have shown that the 5-HT projections to cortical and limbic structuresarise from a neuronal set located in a specific part of the caudal DRN, whichis particularly sensitive to stressful stimuli. The rostral projections fromthese neurons seem to constitute a mesocorticolimbic 5-HT system that modulatesdefense. Based on correlations between the pharmacological efficacy ofantidepressants and anxiolytic drugs in anxiety disorders and the resultsobtained in experimental models of anxiety in humans (discussed below), it hasbeen further suggested that generalized anxiety disorder (GAD) would be relatedto the inhibitory avoidance and conditioned anxiety, whereas PD would berelated to the escape response and innate fear [16]. A schematic representationof the hypothesis on the dual role of 5-HT in anxiety and defense isrepresented in Figure 1.


Panic disorder: is the PAG involved?

Del-Ben CM, Graeff FG - Neural Plast. (2009)

Schematicrepresentation of the dual role of serotonin on fear and anxiety, according toDeakin and Graeff theory.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654309&req=5

fig1: Schematicrepresentation of the dual role of serotonin on fear and anxiety, according toDeakin and Graeff theory.
Mentions: More recently, Lowry etal. [15] have shown that the 5-HT projections to cortical and limbic structuresarise from a neuronal set located in a specific part of the caudal DRN, whichis particularly sensitive to stressful stimuli. The rostral projections fromthese neurons seem to constitute a mesocorticolimbic 5-HT system that modulatesdefense. Based on correlations between the pharmacological efficacy ofantidepressants and anxiolytic drugs in anxiety disorders and the resultsobtained in experimental models of anxiety in humans (discussed below), it hasbeen further suggested that generalized anxiety disorder (GAD) would be relatedto the inhibitory avoidance and conditioned anxiety, whereas PD would berelated to the escape response and innate fear [16]. A schematic representationof the hypothesis on the dual role of 5-HT in anxiety and defense isrepresented in Figure 1.

Bottom Line: Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients.There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients.Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.

View Article: PubMed Central - PubMed

Affiliation: Psychiatry Division, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes, 3900, 14048-900 Ribeirão Preto, SP, Brazil. delben@fmrp.usp.br

ABSTRACT
Data from studies with humans have suggested that abnormalities of midbrain structures, including the periaqueductal gray matter (PAG), could be involved in the neurobiology of panic disorder (PD). The electrical stimulation of the PAG in neurosurgical patients induces panic-like symptoms and the effect of drugs that are effective in the treatment of PD in the simulation of public speaking model of anxiety is in agreement with data from animal models of PD. Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients. There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients. Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.

Show MeSH
Related in: MedlinePlus