Effects of Estrogen on the Serotonergic System and Calcitonin Gene-Related Peptide in Trigeminal Ganglia of Rats

Abstract

BackgroundThe prevalence of migraine is 3-folds higher in females than in males, and it is intricately related to the levels of estrogen. Estrogen may regulate the expression of metabolic enzymes and receptors of serotonin and also calcitonin gene-related peptide (CGRP), which are implicated in migraine pathogenesis.PurposeTo study the effects of estrogen on the components of serotonin system and CGRP in trigeminal ganglia of ovariectomized (OVX) rats.MethodsOVX rats were administered estrogen in silastic tubes and after 48 h, serum estrogen levels were determined. Trigeminal ganglia tissues were used for RT-PCRs of tryptophan hydroxylase (TPH), monoamine oxidase (MAO), serotonin receptors (5-HT1A, 5-HT1B, 5-HT2A), estrogen receptor (ER) and CGRP. Western blots of TPH and MAO were performed.ResultsEstradiol administration to OVX rats increased TPH mRNA levels, while decreased MAO mRNA levels in trigeminal ganglia tissue. Western blot data correlate with the gene expression results. The decreased mRNA levels of serotonin receptors following ovariectomy were restored in estrogen-replenished rats. The induced gene expression of ER in OVX rats was restored following estrogen replenishment.ConclusionEstrogen levels affect the levels of serotonin metabolizing enzymes and its receptors besides CGRP levels. Since TPH and MAO levels regulate circulating and physiologically available serotonin content, the regulation of serotonin metabolizing enzymes suggest a plausible mechanism by which estrogen alleviates migraine in women.

Amitraz changes NE, DA and 5-HT biosynthesis and metabolism mediated by alterations in estradiol content in CNS of male rats

“…Particularly, activity and expression of enzymes that synthesize and metabolize DA, NE and 5-HT are altered by E2 (Babu and Vijayan, 1984;Chaube and Joy, 2011;Donner and Handa, 2009;Luine and Rhodes, 1983;Luine et al, 1973;Rahman and Thomas, 2013;Scardapane and Cardinali, 1977;Schendzielorz et al, 2011;Serova et al, 2002). In addition, E 2 increases mRNA levels and activity of TH and TRH, the major rate limiting enzymes in catecholamines and indoleamines biosynthesis, respectively (Babu and Vijayan, 1984;Chaube and Joy, 2011;Rahman and Thomas, 2013;Serova et al, 2002;Donner and Handa, 2009;Aggarwal et al, 2012;Hiroi et al, 2006). Alternatively, it decreases MAO mRNA levels (Aggarwal et al, 2012).…”

“…In addition, E 2 increases mRNA levels and activity of TH and TRH, the major rate limiting enzymes in catecholamines and indoleamines biosynthesis, respectively (Babu and Vijayan, 1984;Chaube and Joy, 2011;Rahman and Thomas, 2013;Serova et al, 2002;Donner and Handa, 2009;Aggarwal et al, 2012;Hiroi et al, 2006). Alternatively, it decreases MAO mRNA levels (Aggarwal et al, 2012). Interestingly, although COMT activity is considerably resistant to TMX and E 2 effects, E 2 decreases COMT protein levels in prefrontal cortex and TMX increases them (Schendzielorz et al, 2011).…”

Effect of Gonadal Hormones on Neurotransmitters Implicated in the Pathophysiology of Obsessive-Compulsive Disorder: A Critical Review

“…Previous animal studies have demonstrated increased TPH mRNA levels in the dorsal raphe nuclei and trigeminal ganglia [26,27] . Estradiol was later found to specifically increase TPH2 (an isoform exclusively expressed in the central nervous system) mRNA in the dorsal raphe nucleus in macaques and rats [28] .…”

Menopause und Mundgesundheit

“…Sowohl in den oralen Schleimhäuten als auch in den Speicheldrüsen wurden Sexualhormonrezeptoren nachgewiesen [10]. Auch Schmerzempfindung [1] …”