Limbic reductions of 5-HT _1A receptor binding in human temporal lobe epilepsy

Abstract

Patients with severe MTLE show reduced 5-HT1A receptor binding potential in the EEG-focus, and its limbic connections. [(11)C]WAY-100 635 PET may provide additional information to EEG, [18F]FDG PET, and MRI when evaluating patients with intractable seizures. Reductions in 5-HT1A binding in the insula and cingulate suggest a mechanism by which affective symptoms in MTLE may result.

Depressive behavior and selective downregulation of serotonin receptor expression after early-life seizures: Reversal by environmental enrichment

“…PET measurement of 5-HT 1A receptor binding in patients with mesial temporal lobe epilepsy has shown a significant reduction in the epileptogenic hippocampus and its limbic connections [12,29]. Serotonergic hypofunction demonstrated in human temporal lobe epilepsy is consistent with data from present study and from other labs using the KA seizure animal model [30].…”

“…Serotonergic hypofunction demonstrated in human temporal lobe epilepsy is consistent with data from present study and from other labs using the KA seizure animal model [30]. Together these data suggest a potential pathogenetic mechanism for depression in this patient population with high risk for affective disorder [12,31].…”

“…Mutual features of both epilepsy and depression include the link to serotonergic pathways and the involvement of hippocampal and limbic circuitry. In patients with temporal lobe epilepsy, serotonergic receptor binding in the limbic area is decreased [12], while in patients with affective disorder, the efficacy of selective serotonergic reuptake inhibitors (SSRIs) is associated with the activation of regional metabolic rate in the limbic area [13,14]. Increased risk of depression is highly correlated with the cerebral structural and metabolic abnormalities in epilepsy [15,16], while significant reduction in hippocampal volume is observed in major depression [11,17].…”

Kindling epileptogenesis in immature rats leads to persistent depressive behavior

“…On the other hand, Ott et al [11] found that children with complex partial seizures, including TLE and idiopathic generalized epilepsy of the absence type have had similar rates of depression. TLE and depression appear to share several mechanisms, including impairments in serotonergic, noradrenergic, glutamatergic and GABAergic transmission [12][13][14][15].…”

5-HT1A Receptor Binding in Temporal Lobe Epilepsy Patients With and Without Major Depression

“…Two studies showed a significant correlation between current depressive symptoms in TLE patients and reduced 5-HT 1A receptor binding in limbic regions including ipsilaterial hippocampus (19) and ipsilateral anterior cingulate cortex (47). These studies assessed only depressive symptoms, and did not consider whether TLE patients had met diagnostic criteria for a major depressive episode.…”