Cross-talk between the HPA axis and addiction-related regions in stressful situations

Addiction is a worldwide problem that has a negative impact on society by imposing significant costs on health care, public security, and the deactivation of the community economic cycle. Stress is an important risk factor in the development of addiction and relapse vulnerability. Here we review studies that have demonstrated the diverse roles of stress in addiction. Term searches were conducted manually in important reference journals as well as in the Google Scholar and PubMed databases, between 2010 and 2022. In each section of this narrative review, an effort has been made to use pertinent sources. First, we will provide an overview of changes in the Hypothalamus-Pituitary-Adrenal (HPA) axis component following stress, which impact reward-related regions including the ventral tegmental area (VTA) and nucleus accumbens (NAc). Then we will focus on internal factors altered by stress and their effects on drug addiction vulnerability. We conclude that alterations in neuro-inflammatory, neurotrophic, and neurotransmitter factors following stress pathways can impact related mechanisms on craving and relapse susceptibility.

Anti-LINGO-1 improved remyelination and neurobehavioral deficit in cuprizone-induced demyelination

Objective(s):

Central nervous system demyelination is the main feature of multiple sclerosis (MS). The most important unmet need in MS is use of treatments that delay the progression of the disease. Leucine-rich repeat and Immunoglobulin-like domain containing NOGO receptor-interacting protein 1(LINGO-1) have been known as inhibitors of oligodendrocyte differentiation and myelination.

Materials and Methods:

We investigated LINGO-1 antibody effects on remyelination and neurobehavioral deficit using cuprizone-induced demyelination. Animals were randomly divided into three groups (n = 10): (1) Control group; received the regular diet, (2) CPZ group; normal saline was injected intraperitoneally, and (3) Treatment group; LINGO-1 antibody (10 mg/kg) was injected IP once every six days for 3 weeks. We assessed the level of myelin basic protein (MBP), neurofilament heavy chain (NF200), and Brain-derived neuroprotective factor (BDNF) in the corpus callosum (CC) by immunostaining against MBP, NF200, and BDNF.

Results:

We found decreased levels of MBP, NF200, and BDNF in demyelinated CC, and anti-LINGO-1 treatment improved demyelinated structures. Furthermore, motor impairment was measured by Open-field (OFT) and Balance beam tests. In the treatment group, motor impairment was significantly improved.

Conclusion:

These results provide evidence that LINGO-1 antibody can improve remyelination and neurobehavioral deficit.

Repeated Administration of Baclofen Modulates TRPV-1 Channel Expression by PKC Pathway in Dorsal Root Ganglia of Spinal Cord in a Morphine Tolerance Model of Rats

Background:

Tolerance and dependence to anti-nociceptive effect of morphine restricted its use. Nowadays co-administration of morphine and other drugs suggests diminishing this tolerance. Baclofen is one of the drugs that may be beneficial in the attenuation of tolerance to morphine. Studies have shown that changes in TRPV-1 expression during administration of morphine have a pivotal role in developing morphine tolerance. Therefore, the effect of baclofen on TRPV-1 expression during chronic administration of morphine was investigated in this study.

Methods:

A total of 48 rats were divided into four groups of control, morphine single injection, morphine tolerance, and morphine tolerance + baclofen. To induce morphine tolerance in rats, animals received 10 mg/kg of i.p. morphine sulfate once a day for 10 days. In the treatment group, baclofen (0.5 mg/kg) was injected for 10 days, before morphine injection. Finally, to evaluate baclofen treatment on morphine analgesia and hyperalgesia, thermal hyperalgesia and formalin test were used. TRPV-1 and PKC expression and protein production in DRG of spinal cord were then evaluated by real-time PCR and Western blot.

Results:

In baclofen treatment group, thermal hyperalgesia and formalin test improved in comparison with morphine tolerance group. In morphine tolerance group, both TRPV-1/PKC gene expression and protein levels increased in comparison with the control group. However, following the baclofen treatment, the TRPV-1 and PKC levels decreased.

Conclusion:

Baclofen can enhance anti-nociceptive effect of morphine by modulating TRPV-1 channel and PKC activity.

Hypoxic-conditioned medium from adipose tissue mesenchymal stem cells improved neuroinflammation through alternation of toll like receptor (TLR) 2 and TLR4 expression in model of Alzheimer's disease rats

Microglia have a pivotal role to initiate immune responses in AD brains through toll-like receptors and induce neuroinflammation. Adipose tissue mesenchymal stem cells (ATSCs) secret many neurotrophic and anti-inflammatory factors called conditioned medium (CM). Many studies have demonstrated that CM of mesenchymal stem cells facilitate regeneration and attenuates inflammation in many disorders. To this purpose, the effect of ATSCs-conditioned medium (ATSC-CM) on brain inflammation and the role of toll-like receptors were investigated in this study. Seventy-two rats were randomly divided into 6 groups: control, sham, sham+ATSC-CM: 200μl ATSC-CM once a day intraperitoneally for 8 days, AD group injected the Aβ1-40 intra-hippocampal, AD+ASC-CM, which was injected Aβ1-40 intra-hippocampal and 200μl ATSC-CM once a day intraperitoneally for 8 days and AD+ rivastigmine: was injected Aβ1-40 intra-hippocampal and received rivastigmine (0.6 mg/kg) orally once a day for 2 weeks. Memory and learning were measured by Morris water maze and novel object recognition tests. For detection of beta-amyloid plaque, Congo red staining was used, and neuronal survival was assessed by Nissl staining. Expression of TLR2 and TLR4 was measured by real-time PCR, and finally, to assess inflammation markers (IL-1β and TNF-α) in the hippocampus, ELISA kits were used. In treatment group spatial and recognition memory significantly was improved. ATSC-CM administration decreased beta amyloid plaques and enhanced neuronal survival in AD brain rats. In addition, TLR2 and TLR4 expression decreased in treatment group. Results also showed that ATSC-CM reduced IL-1β and TNF-α as inflammation markers. ATSC-CM improved memory deficit, decreased beta amyloids formation, increased neuron survival, and attenuated inflammation by reducing the expression of TLRs.