Effects of acute or 3-day treatments of Hypericum caprifoliatum Cham. & Schltdt. (Guttiferae) extract or of two established antidepressants on basal and stress-induced increase in serum and brain corticosterone levels

Abstract

Since depressive patients present alterations in the hypothalamo-pituitary-adrenal (HPA) axis that are normalised by antidepressants, this HPA axis has been considered as a target of their actions. We have investigated the mechanism of action of a cyclohexane extract of Hypericum caprifoliatum (HCP), which displays antidepressant like activity, by studying, in mice, the influence of HCP and of two established antidepressant drugs, imipramine and bupropion, administered either acutely or semi-chronically (once a day, three consecutive days), on serum and brain cortex corticosterone levels, either in basal conditions or shortly after a forced-swimming session (FSS). Administered acutely, imipramine (20 mg/kg, per os (p.o.)), bupropion (30 mg/kg, p.o.) and HCP (360 mg/kg, p.o.) significantly reduced the immobility time and had no effects on FSS-induced increase of serum and cortical corticosterone levels. Conversely, 3 days repeated treatment with imipramine or bupropion resulted in a significant reduction of immobility time and FSS-induced increase of serum and cortical corticosterone levels. In a different way, repeated treatment with HCP significantly reduced the immobility time and only cortical corticosterone levels in stressed mice. These results indicate that short-term treatments with antidepressants are sufficient to induce modifications in the HPA axis reactivity to stress; and that apparently HCP has an influence on corticosterone levels by a mechanism diverse from the other tested antidepressants.

Study of antidepressant-like activity of an enriched phloroglucinol fraction obtained fromHypericum caprifoliatum

“…Since the hippocampus is a region particularly sensitive to stress effects (McEwen, 2001) and different morphological and neurochemical effects have been reported in hippocampus after depressive states (Sheline et al, 2003), we decided to evaluate the effect of HC1 on the activity of Na þ , K þ ATPase on this brain region. We also investigated the effect of HC1 on cerebral cortex Na þ , K þ ATPase activity, once our group has already reported that a H. caprifoliatum extract reduced cortical corticosterone levels in stressed mice (Viana et al, 2008). In the present study, repeated HC1 administration (360 mg/ kg, p.o.…”

“…In addition, Goto et al (1995) demonstrated in rats that acute swimming stress resulted in significant increases of ouabain-like compound levels in plasma and adrenal. Furthermore, steroid hormones, in particular, corticosteroids, have specific long-and short-term regulatory effects on the Na þ , K þ ATPase (Therien & Blostein, 2000) and it has already been proved that a short forced swimming session increases both plasma and cortical corticosterone levels in mice (Viana et al, 2008). The antidepressants imipramine and bupropione as well as a lipophilic extract of H. caprifoliautm were able to reduce the cortical increase of corticosterone induced by forced swimming (Viana et al, 2008).…”

“…or 2% polysorbate 80 solution in saline (NaCl 0.9%) 30 min before the test. This dose was chosen based on previous studies of our group (Viana et al, 2005(Viana et al, , 2008. All treatments were administered at 10 ml/kg body weight.…”

“…These phloroglucinol derivatives were proposed as chemotaxonomic markers for the southern Brazilian species (Nör et al, 2004). Among the species studied, Hypericum caprifoliatum Cham & Schlecht showed promising results in the forced swimming test (FST), which predicts antidepressant activity (Daudt et al, 2000;Viana et al, 2005Viana et al, , 2008. However, the molecular mechanisms by which these H. caprifoliatum extracts exert this antidepressant-like effect remains unclear.…”

Is Forced Swimming Immobility a Good Endpoint for Modeling Negative Symptoms of Schizophrenia? - Study of Sub-Anesthetic Ketamine Repeated Administration Effects

“…Locomotion in response to novelty and novel object recognition (tasks related to positive and cognitive impairments presented by schizophrenia patients, respectively) were also performed in order to make a broader evaluation. The methodology used was based on that described by Noda et al (1995Noda et al ( , 1997 with some modifications according to the standard protocol used by our group (Viana et al 2008, Borsoi et al 2015a. Animals were habituated to laboratory conditions one hour before exposition to the forced swimming session.…”