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Effects of long-term administration of hypericum extracts on the affinity and density of the central serotonergic 5-HT1 A and 5-HT2 A receptors.
Pharmacopsychiatry 1997; 30 Suppl 2:113-6P

Abstract

Extracts of St. John's wort, Hypericum perforatum L. (Hypericaceae), are used as a phytotherapeutic antidepressant. A number of clinical studies demonstrate that their antidepressive potency is comparable to tricyclic antidepressants (TCA). Although the therapeutic effect of hypericum extracts is well documented, very little is known about the molecular mode of action. As the improvement of the depressive symptoms with both TCA and hypericum extracts only occurs significantly after a lag phase of 10 to 14 days, it is assumed that the medication causes long-term adaptations within the central nervous system. In this context, serotonergic (5-HT) receptors are of special interest. Therefore, we investigated possible alterations in affinity and density of 5-HT1 A and 5-HT2 A receptors caused by long-term treatment of rats with St. John's wort. The brain without cerebellum and brain stem of rats, treated daily for 26 weeks with a commercially available hypericum extract (2700 mg/kg LI 160) were used for membrane preparations. Affinity (KD) and amount (Bmax) of serotonergic receptors were determined by employing receptor binding assays using 3 H-8-OH-DPAT and 3H-Ketanserin as selective radioligands for the 5-HT1 A and the 5-HT2 A receptors, respectively. We found that in hypericum-treated rats the number of both 5-HT1 A and 5-HT2 A receptors were significantly increased by 50% compared to controls, whereas the affinity of both serotonergic receptors remained unaltered. The data suggest an upregulation of 5-HT1 A and 5-HT2 A receptors due to prolonged administration of hypericum extracts. These results are consistent with a modification of the expression levels of serotonergic receptors caused by synthetic antidepressants.

Authors+Show Affiliations

Department of Naturheilkunde, Ulm University, Germany.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9342771

Citation

Teufel-Mayer, R, and J Gleitz. "Effects of Long-term Administration of Hypericum Extracts On the Affinity and Density of the Central Serotonergic 5-HT1 a and 5-HT2 a Receptors." Pharmacopsychiatry, vol. 30 Suppl 2, 1997, pp. 113-6.
Teufel-Mayer R, Gleitz J. Effects of long-term administration of hypericum extracts on the affinity and density of the central serotonergic 5-HT1 A and 5-HT2 A receptors. Pharmacopsychiatry. 1997;30 Suppl 2:113-6.
Teufel-Mayer, R., & Gleitz, J. (1997). Effects of long-term administration of hypericum extracts on the affinity and density of the central serotonergic 5-HT1 A and 5-HT2 A receptors. Pharmacopsychiatry, 30 Suppl 2, pp. 113-6.
Teufel-Mayer R, Gleitz J. Effects of Long-term Administration of Hypericum Extracts On the Affinity and Density of the Central Serotonergic 5-HT1 a and 5-HT2 a Receptors. Pharmacopsychiatry. 1997;30 Suppl 2:113-6. PubMed PMID: 9342771.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of long-term administration of hypericum extracts on the affinity and density of the central serotonergic 5-HT1 A and 5-HT2 A receptors. AU - Teufel-Mayer,R, AU - Gleitz,J, PY - 1997/10/29/pubmed PY - 1997/10/29/medline PY - 1997/10/29/entrez SP - 113 EP - 6 JF - Pharmacopsychiatry JO - Pharmacopsychiatry VL - 30 Suppl 2 N2 - Extracts of St. John's wort, Hypericum perforatum L. (Hypericaceae), are used as a phytotherapeutic antidepressant. A number of clinical studies demonstrate that their antidepressive potency is comparable to tricyclic antidepressants (TCA). Although the therapeutic effect of hypericum extracts is well documented, very little is known about the molecular mode of action. As the improvement of the depressive symptoms with both TCA and hypericum extracts only occurs significantly after a lag phase of 10 to 14 days, it is assumed that the medication causes long-term adaptations within the central nervous system. In this context, serotonergic (5-HT) receptors are of special interest. Therefore, we investigated possible alterations in affinity and density of 5-HT1 A and 5-HT2 A receptors caused by long-term treatment of rats with St. John's wort. The brain without cerebellum and brain stem of rats, treated daily for 26 weeks with a commercially available hypericum extract (2700 mg/kg LI 160) were used for membrane preparations. Affinity (KD) and amount (Bmax) of serotonergic receptors were determined by employing receptor binding assays using 3 H-8-OH-DPAT and 3H-Ketanserin as selective radioligands for the 5-HT1 A and the 5-HT2 A receptors, respectively. We found that in hypericum-treated rats the number of both 5-HT1 A and 5-HT2 A receptors were significantly increased by 50% compared to controls, whereas the affinity of both serotonergic receptors remained unaltered. The data suggest an upregulation of 5-HT1 A and 5-HT2 A receptors due to prolonged administration of hypericum extracts. These results are consistent with a modification of the expression levels of serotonergic receptors caused by synthetic antidepressants. SN - 0176-3679 UR - https://www.unboundmedicine.com/medline/citation/9342771/Effects_of_long_term_administration_of_hypericum_extracts_on_the_affinity_and_density_of_the_central_serotonergic_5_HT1_A_and_5_HT2_A_receptors_ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-2007-979530 DB - PRIME DP - Unbound Medicine ER -