Platelet Serotonin Transporter Function and Heart Rate Variability in Patients with Panic Disorder

Abstract

Many studies showed abnormal serotonin transporter (5-HTT) function and heart rate variability (HRV) in panic disorder patients. The present study investigated the relationship between HRV power spectral analysis findings and platelet serotonin uptake in panic disorder patients. Short-term HRV over 5 min and platelet serotonin transporter uptake parameters (Vmax and Km) were measured both in 45 patients with panic disorder and in 30 age-matched normal healthy control subjects. Low frequency power (LF) normalized unit (nu) and LF/high frequency power (HF) were significantly higher, whereas HF and HF nu were lower in the patient group than in the control group. Vmax and Km were all significantly lower (i.e., reflects decreased 5-HTT function) in patients with panic disorder than in normal controls. In the patient group, Km was negatively correlated with LF/HF and LF nu whereas no such correlations between them were found in the control group. By multivariate analysis based on multiple hierarchical linear regression, a low Km independently predicted an increased LF nu even after controlling for age, sex, and body mass index in the patient group. These results suggest that impaired 5-HTT function is closely related to dysregulation of autonomic nervous system in panic disorder.

Increased mean platelet volume in patients with panic disorder

“… 30 In one study, platelet 5-HT uptake maximal velocity ( V max) and its associated affinity constant ( K m ) were found to be lower in PD patients than in normal control subjects. 41 In this study, Kang et al reported that patients with PD showed abnormalities in platelet 5-HTT function; furthermore, they found that after 12 weeks of paroxetine treatment, the K m values of platelet serotonin transporters increased in parallel to clinical improvement. They speculated that impaired 5-HTT function might be related to the dysregulation of the autonomic nervous system in PD.…”

“…They speculated that impaired 5-HTT function might be related to the dysregulation of the autonomic nervous system in PD. 41 …”

Decreased cardiac vagal control in drug‐naive patients with panic disorder: A case‐control study in Taiwan

“…In a recent Korean study, there were no significant differences in time‐domain indices of HRV between PD patients and controls; however, frequency‐domain analysis of HRV revealed that LF normalized unit (nu) and LF/HF ratio were significantly higher, whereas HF and HF nu were lower in PD patients than in controls (Kang et al ., ). Similarly, Alvarenga et al .…”

“…(i) Kang et al . () suggested that impaired 5‐HTT function, as measured by platelet 5‐HTT uptake, was closely related to ANS dysregulation in PD. (ii) Tucker et al .…”

Anxiety Level and Cardiac Autonomic Modulations in Coronary Artery Disease and Cardiac Syndrome X Patients

“…Based on measures of CAM, the level of anxiety is expected to correlate inversely with HF and proportionally with LF and LF/HF [45]. Failure of our results to demonstrate the expected trend between TMAS and measures of CAM may partly be explained by the relatively low anxiety levels in the studied groups.…”