ISSN 2326-7291
International Journal of Public Health and Epidemiology ISSN 2326-7291 Vol. 14 (2), pp. 001-009, February, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals
Full Length Research Paper
The Serotonergic System within the Rat Heart: Insights and Characterization of Its Intrinsic Mechanism
Gabriel Manjarrez-Gutiérrez1,2*, Teresa Neri-Gómez1, Alfonso Boyzo-Montes de Oca3 and Jorge Hernández-Rodríguez3
1Laboratory of Molecular Pathology, Cardiology Hospital, National Medical Center (CMN-SXXI), Mexican Institute of Social Security (IMSS), Mexico City, Mexico.
2Medical Research Unit in Neurological Diseases, Specialties Hospital, CMN-SXXI, IMSS, México, DF, México
3Laboratory of Neurontogeny, Department of Physiology, Biophysics and Neurosciences, Center of Research and Advanced Studies (CINVESTAV) IPN, Mexico City, Mexico.
Accepted 10 November, 2024
Abstract
The objective of this study was to characterize biochemically and immunohistochemically an intrinsic serotonergic system in rat heart. Male Wistar rats were used with an average body weight of 250 ± 10 g. Rats were adapted for 2 weeks to standard animal laboratory conditions. Hearts were later obtained to determine the principal components of the serotoninergic system using immunohistochemistry and Western blot for tryptophan-5-hydroxylase (TPH) 1 or 2, serotonin transporter (SERT) and serotoninergic receptors 5-HT1B, 5-HT2A, 5-HT2B and 5-HT4. Activity of TPH, L-tryptophan (L-Trp), 5-hydroxytryptamine (serotonin, 5-HT) and 5-hydroxyindolacetic acid (5-HIAA) were also determined by high-resolution liquid chromatography. Immunopositive cardiomyocytes for both isoforms of TPH were observed. There was a greater expression of TPH2in relation to TPH1. Immunoreactivity for SERT and 5-HT1B, 5-HT2A, 5-HT2B and 5-HT4receptors was also observed in cardiomyocytes. TPH activity, L-Trp, 5-HT and 5-HIAA concentrations were also demonstrated in heart tissue. These findings support the fact that cardiomyocytes synthesize, utilize and reuptake 5-HT, which constitutes an intrinsic serotoninergic system that actively participates as an autocrine and paracrine modulation system of heart activities.
Key words: Cardiomyocytes, serotonin, tryptophan-5-hydroxylase, SERT, serotoninergic receptors.