Antidepressant effects of crocin and its effects on transcript and protein levels of CREB, BDNF, and VGF in rat hippocampus

BACKGROUND: Antidepressants have been shown to affect levels of brain-derived neurotrophic factor (BDNF) and VGF (non-acronymic) whose transcriptions are dependent on cAMP response element binding protein (CREB) in long term treatment. The aim of this study was to verify the subacute antidepressant effects of crocin, an active constituent of saffron (Crocus sativus L.), and its effects on CREB, BDNF, and VGF proteins, transcript levels and amount of active, phosphorylated CREB (P-CREB) protein in rat hippocampus. METHODS: Crocin (12.5, 25, and 50 mg/kg), imipramine (10 mg/kg; positive control) and saline (1 mL/kg; neutral control) were administered intraperitoneally (IP) to male Wistar rats for 21 days. The antidepressant effects were studied using the forced swimming test (FST) on day 21 after injection. Protein expression and transcript levels of genes in the rat hippocampus were evaluated using western blot and quantitative reverse transcription-polymerase chain reaction (qRT-PCR), respectively. RESULTS: Crocin significantly reduced the immobility time in the FST. Western blot analysis showed that 25 and 50 mg/kg of crocin increased the levels of CREB and BDNF significantly and dose dependently. All doses of crocin increased the VGF levels in a dose-dependent manner. Levels of p-CREB increased significantly by 50 mg/kg dose of crocin. Only 12.5 mg/kg crocin could significantly increase the transcript levels of BDNF. No changes in CREB and VGF transcript levels were observed in all groups. CONCLUSIONS: These results suggest that crocin has antidepressant-like action by increasing CREB, BDNF and VGF levels in hippocampus

Effects of berberine on acquisition and reinstatement of morphine-induced conditioned place preference in mice

Objective: It has been shown that berberine, a major component of Berberis vulgaris extract, modulates the activity of several neurotransmitter systems including dopamine (Da) and N-methyl-D-aspartate (NMDA) contributing to rewarding and reinforcing effects of morphine. Drug craving and relapsing even after a long time of abstinence therapy are the most important problems of addiction. In the present study, we investigated the alleviating effects of berberine on the acquisition and reinstatement of morphine-induced conditioned place preference (CPP) in mice. Materials and Methods: In male NMRI mice, the acquisition of CPP was established by 40 mg/kg of morphine sulphate injection and extinguished after the extinction training and reinstated by a 10 mg/kg injection of morphine.  The effects of different doses of berberine (5, 10, and 20 mg/kg) on the acquisition and reinstatement induced by morphine were evaluated in a conditioned place preference test. Results: The results showed that intraperitoneal administration of berberine (5, 10, and 20 mg/kg) did not induce conditioned appetitive or aversive effects. Injection of berberine (10 and 20 mg/kg) 2 h before the morphine administration reduced acquisition of morphine-induced CPP. In addition, same doses of berberine significantly prevented the reinstatement of morphine-induced CPP. Conclusion: These results suggest that berberine can reduce the acquisition and reinstatement of morphine-induced conditioned place preference and may be useful in treatment of morphine addiction

Effects of silymarin on neuropathic pain and formalin-induced nociception in mice

Objective(s):Based on the previous reports, silymarin can suppress nitric oxide, prostaglandin E2 (PGE2), leukotrienes, cytokines production, and neutrophils infiltration. Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain. The present study investigates the analgesic effects of silymarin in chemical nociception and a model of neuropathic pain. Materials and Methods: Chemical nociception was produced by injection of 20 µl of formalin (0.5% formaldehyde in saline) into the plantar region of the right hind paw. A sciatic-nerve ligated mouse was applied as the model of neuropathic pain and the antinociceptive response of silymarin was examined 14 days after unilateral nerve-ligation using the hot plate test. Results:The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner. Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception. Conclusion:Results of the present study indicated that repeated administration of silymarin prevents the formalin-induced nociceptive behavior. However, it is not effective in the treatment of sciatic neuropathic pain

Effects of silymarin on neuropathic pain and formalin- induced nociception in mice

Objective(s): Based on the previous reports, silymarin can suppress nitric oxide, prostaglandin E2 (PGE2), leukotrienes, cytokines production, and neutrophils infiltration. Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain. The present study investigates the analgesic effects of silymarin in chemical nociception and a model of neuropathic pain. Materials and Methods: Chemical nociception was produced by injection of 20 µl of formalin (0.5% formaldehyde in saline) into the plantar region of the right hind paw. A sciatic-nerve ligated mouse was applied as the model of neuropathic pain and the antinociceptive response of silymarin was examined 14 days after unilateral nerve-ligation using the hot plate test. Results: The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner. Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception. Conclusion: Results of the present study indicated that repeated administration of silymarin prevents the formalin-induced nociceptive behavior. However, it is not effective in the treatment of sciatic neuropathic pain

Inositol Trisphosphate Receptors and Nuclear Calcium in Atrial Fibrillation

RATIONALE: The mechanisms underlying atrial fibrillation (AF), the most common clinical arrhythmia, are poorly understood. Nucleoplasmic Ca(2+) regulates gene-expression, but the nature and significance of nuclear Ca(2+)-changes in AF are largely unknown. OBJECTIVE: To elucidate mechanisms by which AF alters atrial cardiomyocyte (CM) nuclear Ca(2+) ([Ca(2+)](Nuc)) and Ca(2+)/calmodulin-dependent protein kinase-II (CaMKII)-related signaling. METHODS AND RESULTS: Atrial CMs were isolated from control and AF-dogs (kept in AF by atrial tachypacing [600 bpm × 1 week]). [Ca(2+)](Nuc) and cytosolic [Ca(2+)] ([Ca(2+)](Cyto)) were recorded via confocal microscopy. Diastolic [Ca(2+)](Nuc) was greater than [Ca(2+)](Cyto) under control conditions, while resting [Ca(2+)](Nuc) was similar to [Ca(2+)](Cyto); both diastolic and resting [Ca(2+)](Nuc) increased with AF. Inositol-trisphosphate-receptor (IP(3)R) stimulation produced larger [Ca(2+)](Nuc) increases in AF versus control CMs, and IP(3)R-blockade suppressed the AF-related [Ca(2+)](Nuc)-differences. AF upregulated nuclear protein-expression of IP(3)R-type 1 (IP(3)R1) and of phosphorylated CaMKII (immunohistochemistry and immunoblot), while decreasing the nuclear/cytosolic expression-ratio for histone deacetylase type-4 (HDAC4). Isolated atrial CMs tachypaced at 3 Hz for 24 hours mimicked AF-type [Ca(2+)](Nuc) changes and L-type calcium current (I(CaL)) decreases versus 1-Hz-paced CMs; these changes were prevented by IP(3)R knockdown with short-interfering RNA directed against IP(3)R1. Nuclear/cytosolic HDAC4 expression-ratio was decreased by 3-Hz pacing, while nuclear CaMKII and HDAC4 phosphorylation were increased. Either CaMKII-inhibition (by autocamtide-2-related peptide) or IP(3)R-knockdown prevented the CaMKII-hyperphosphorylation and nuclear-to-cytosolic HDAC4 shift caused by 3-Hz pacing. In human atrial CMs from AF patients, nuclear IP(3)R1-expression was significantly increased, with decreased nuclear/non-nuclear HDAC4 ratio. MicroRNA-26a was predicted to target ITPR1 (confirmed by Luciferase assay) and was downregulated in AF atrial CMs; microRNA-26a silencing reproduced AF-induced IP(3)R1 upregulation and nuclear diastolic Ca(2+)-loading. CONCLUSION: AF increases atrial CM nucleoplasmic Ca(2+)-handling by IP(3)R1-upregulation involving miR-26a, leading to enhanced IP(3)R1-CaMKII-HDAC4 signaling and I(CaL)-downregulation