Serotonin Function in Panic Disorder: Important, But Why?

Abstract

The essential role of serotonin (5-hydroxytryptamine (5-HT)) system in the neurobiology and pharmacotherapy of panic disorder (PD) continues to be a topic of intensive interdisciplinary research. Interest in the involvement of 5-HT in PD has been fuelled by clinical studies demonstrating that medications increasing the synaptic availability of 5-HT, such as selective 5-HT re-uptake inhibitors, are effective in the treatment of PD. Rival theories of 5-HT deficiency vs excess have attempted to explain the impact of 5-HT function in PD. In the past decade, knowledge of the role of 5-HT in the neurobiology of PD has expanded dramatically due to much new research including experimental, treatment, brain-imaging, and genetic studies. The current review attempts to summarize the new data and their implications. The challenge and treatment studies generally confirm the specific inhibitory influence of 5-HT on panicogenesis. The brainimaging studies in PD patients demonstrate functional and clinically relevant alterations in various elements of 5-HT system affecting the neurocircuitry of panic. The findings of genetic association studies suggest that certain 5-HT-related genes may contribute to the susceptibility to PD; however, these data are rather limited and inconsistent. It appears that, even if not the primary etiological factor in PD, the 5-HT function conveys important vulnerability, as well as adaptive factors. A better understanding of these processes may be critical in achieving progress in the treatment of patients suffering from PD.

Reactivity to 35% carbon dioxide in bulimia nervosa and panic disorder

“…One would expect high degrees of reactivity to 35% CO 2 in those with a diagnosis of PD, as the CO 2 provocation is known to aggravate panic in those with panic histories (e.g., Perna et al, 1995a). Additionally, evidence suggests that the serotonergic abnormalities that occur in PD (Coplan et al, 1992;Maron and Shlik, 2006) are associated with enhanced reactivity to CO 2 . However, a history of unexpected panic attacks is an exclusionary criterion for participants with BN in the current study; thus we cannot attribute hyperreactivity in BN to panic history as we potentially could in previous studies, including those using sodium lactate (e. g., Lindy et al, 1988).…”

Effect of Zuogui Pill (左归丸) on monoamine neurotransmitters and sex hormones in climacteric rats with panic attack

“…The second school of thought proposes that 5-HT defi ciency in specifi c brain regions might cause panic attacks. (11) To date, most evidence has supported the assumption of 5-HT deficiency or hypofunction. In a single-photon emission computed tomography study, the patients with current panic attacks exhibited a significant decrease in 5-HT transporter (5-HTT) binding in the midbrain, the temporal lobes and the thalamus compared with the controls.…”

Norepinephrine-mediated Regulation of 5HT1 Receptor Functioning in Human Platelets

“…Accumulating evidences from clinical, experimental research and genetic studies point to substantial impact of the 5HT system on the neurobiology of anxiety disorders [40,41]. Importantly, the 5HT system affects and is influenced by many other neurotransmitters in brain structures essential for the processing and expression of anxiety.…”