title: Central and peripheral effects of Sutherlandia frutescens on the response to acute psychological stress.
abstract: Sutherlandia frutescens is widely used in indigenous medicine for the treatment of stress- and anxiety-related disorders, and although anecdotal evidence has been scientifically confirmed, relatively little data are available on its potential mechanisms of action. We manipulated a rodent model of acute psychological stress by acutely administering a low dose (4 mg/kg body mass) of S. frutescens extract 30 min prior to stress exposure (1 h restraint), to elucidate both its central and peripheral mechanisms of action in the context of acute stress. After 1 h of exposure to stress, acute restraint resulted in a significant increase in plasma corticosterone levels (56 ± 33 versus 499 ± 50 ng/ml; P < 0.0001) and anterior pituitary adrenocorticotropic hormone (ACTH) levels (0.066 ± 0.017 versus 0.202 ± 0.033% fluorescent area; P = 0.07), while decreasing hippocampal glucocorticoid receptor (GR) and gamma-aminobutyric acid (GABA)(A)α1 receptor levels (both P < 0.05). While the low dose of S. frutescens administered did not seem to have an effect on the down-stream stress response, it abolished the stress-induced down-regulation of GR, in a manner independent of GABA(A)α1 receptor. Results suggest a non-sedative effect of low-dose S. frutescens and points to central mechanisms of action that is in support of the anecdotal claims for its effectiveness as complimentary treatment in chronic stress-associated diseases.
authors.affiliation: Department Physiological Sciences, Stellenbosch University, Stellenbosch, 7602, South Africa.
authors.forename: Carine
authors.initials: C
authors.lastname: Smith
authors.forename: Marthinus Janse
authors.initials: MJ
authors.lastname: van Vuuren
mesh_terms: D000818:Animals; D003345:Corticosterone / Q000097:blood; D015536:Down-Regulation / Q000187:drug effects; D007887:Fabaceae / Q000737:chemistry*; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D008297:Male; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000096:biosynthesis; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis; D013315:Stress, Psychological / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D013997:Time Factors
chemical_list: D010936:Plant Extracts; D011963:Receptors, GABA-A; D011965:Receptors, Glucocorticoid; D003345:Corticosterone
keywords: ACTH; Glucocorticoid receptor; gamma-aminobutyric acid receptor; restraint