Expression of type one cannabinoid receptor in different subpopulation of kisspeptin neurons and kisspeptin afferents to GnRH neurons in female mice

Adult Neurogenesis Is Regulated by the Endocannabinoid and Kisspeptin Systems

Neurogenesis is considered the most robust form of plasticity in the adult brain. To better decipher this process, we evaluated the potential crosstalk of Kisspeptin and Endocannabinoid Systems (KPS and ECS, respectively) on hippocampal neurogenesis. Male adolescent rats were exposed to kisspeptin-10 (KP10) and the endocannabinoid anandamide (AEA) administered alone or in combination with the type 1 cannabinoid receptor (CB1R) antagonist SR141716A. The expression of Kiss1 and Kisspeptin receptor (Kiss1R) has been characterized for the first time in rat hippocampus together with the expression of the CB1R and the Transient Receptor Potential Vanilloid 1 ion channel receptor (TRPV1). Results show that both systems inhibit neurogenesis by reducing the extracellular signal-regulated kinase (ERK) signaling. Despite little differences in the expression of Kiss1R and CB1R, TRPV1 is enhanced by both KP10 and AEA treatments, suggesting TRPV1 as a common thread. KP10 administration reduces CB1R expression in the dentate gyrus, while AEA does not. KPS, unlike ECS, promotes the expression of estrogen receptor α (ER-α) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), also upregulating sirtuin 1 (SIRT1), brain-derived-neurotrophic factor (BDNF), and c-Jun. These findings suggest that the interaction between ECS and KPS could be involved in the fine-tuning of neurogenesis, highlighting a novel role for KPS.

The role of the endocannabinoid system in the pathogenesis and treatment of epilepsy

Epilepsy is a group of chronic neurological brain disorders characterized by recurrent spontaneous unprovoked seizures, which are accompanied by significant neurobiological, cognitive, and psychosocial impairments. With a global prevalence of approximately 0.5-1 % of the population, epilepsy remains a serious public health concern. Despite the development and widespread use of over 20 anticonvulsant drugs, around 30 % of patients continue to experience drug-resistant seizures, leading to a substantial reduction in quality of life and increased mortality risk. Given the limited efficacy of current treatments, exploring new therapeutic approaches is critically important. In recent years, Gi-protein-coupled receptors, particularly cannabinoid receptors CB1 and CB2, have garnered increasing attention as promising targets for the treatment seizures and prevention of epilepsy. Emerging evidence suggests a significant role of the cannabinoid system in modulating neuronal activity and protecting against hyperexcitability, underscoring the importance of further research in this area. This review provides up-to-date insights into the pathogenesis and treatment of epilepsy, with a special focus on the role of the cannabinoid system, highlighting the need for continued investigation to develop more effective therapeutic strategies.

Cannabis Sativa targets mediobasal hypothalamic neurons to stimulate appetite

The neurobiological mechanisms that regulate the appetite-stimulatory properties of cannabis sativa are unresolved. This work examined the hypothesis that cannabinoid-1 receptor (CB1R) expressing neurons in the mediobasal hypothalamus (MBH) regulate increased appetite following cannabis vapor inhalation. Here we utilized a paradigm where vaporized cannabis plant matter was administered passively to rodents. Initial studies in rats characterized meal patterns and operant responding for palatable food following exposure to air or vapor cannabis. Studies conducted in mice used a combination of in vivo optical imaging, electrophysiology and chemogenetic manipulations to determine the importance of MBH neurons for cannabis-induced feeding behavior. Our data indicate that cannabis vapor increased meal frequency and food seeking behavior without altering locomotor activity. Importantly, we observed augmented MBH activity within distinct neuronal populations when mice anticipated or consumed food. Mechanistic experiments demonstrated that pharmacological activation of CB1R attenuated inhibitory synaptic tone onto hunger promoting Agouti Related Peptide (AgRP) neurons within the MBH. Lastly, chemogenetic inhibition of AgRP neurons attenuated the appetite promoting effects of cannabis vapor. Based on these results, we conclude that MBH neurons contribute to the appetite stimulatory properties of inhaled cannabis.

The interplay between kisspeptin and endocannabinoid systems modulates male hypothalamic and gonadic control of reproduction in vivo

Introduction

Male reproduction is under the control of the hypothalamus-pituitary-gonadal (HPG) axis. The endocannabinoid system (ECS) and the kisspeptin system (KS) are two major signaling systems in the central and peripheral control of reproduction, but their possible interaction has been poorly investigated in mammals. This manuscript analyzes their possible reciprocal modulation in the control of the HPG axis.

Materials and methods

Adolescent male rats were treated with kisspeptin-10 (Kp10) and endocannabinoid anandamide (AEA), the latter alone or in combination with the type 1 cannabinoid receptor (CB1) antagonist rimonabant (SR141716A). The hypothalamic KS system and GnRH expression, circulating sex steroids and kisspeptin (Kiss1) levels, and intratesticular KS and ECS were evaluated by immunohistochemical and molecular methods. Non-coding RNAs (i.e., miR145-5p, miR-132-3p, let7a-5p, let7b-5p) were also considered.

Results

Circulating hormonal values were not significantly affected by Kp10 or AEA; in the hypothalamus, Kp10 significantly increased GnRH mRNA and aromatase Cyp19, Kiss1, and Kiss1 receptor (Kiss1R) proteins. By contrast, AEA treatment affected the hypothalamic KS at the protein levels, with opposite effects on the ligand and receptor, and SR141716A was capable of attenuating the AEA effects. Among the considered non-coding RNA, only the expression of miR145-5p was positively affected by AEA but not by Kp10 treatment. Localization of Kiss1+/Kiss1R+ neurons in the arcuate nucleus revealed an increase of Kiss1R-expressing neurons in Kp10- and AEA-treated animals associated with enlargement of the lateral ventricles in Kp10-treated animals. In the brain and testis, the selected non-coding RNA was differently modulated by Kp10 or AEA. Lastly, in the testis, AEA treatment affected the KS at the protein levels, whereas Kp10 affected the intragonadal levels of CB1 and FAAH, the main modulator of the AEA tone. Changes in pubertal transition-related miRNAs and the intratesticular distribution of Kiss1, Kiss1R, CB1, and CB2 following KP and AEA treatment corroborate the KS-ECS crosstalk also showing that the CB1 receptor is involved in this interplay.

Conclusion

For the first time in mammals, we report the modulation of the KS in both the hypothalamus and testis by AEA and revealed the KP-dependent modulation of CB1 and FAAH in the testis. KP involvement in the progression of spermatogenesis is also suggested.

Recent Advances in Endocannabinoid System Targeting for Improved Specificity: Strategic Approaches to Targeted Drug Delivery

Opportunities for developing innovative and intelligent drug delivery technologies by targeting the endocannabinoid system are becoming more apparent. This review provides an overview of strategies to develop targeted drug delivery using the endocannabinoid system (ECS). Recent advances in endocannabinoid system targeting showcase enhanced pharmaceutical therapy specificity while minimizing undesirable side effects and overcoming formulation challenges associated with cannabinoids. This review identifies advances in targeted drug delivery technologies that may permit access to the full pharmacotherapeutic potential of the ECS. The design of optimized nanocarriers that target specific tissues can be improved by understanding the nature of the signaling pathways, distribution in the mammalian body, receptor structure, and enzymatic degradation of the ECS. A closer look at ligand-receptor complexes, endocannabinoid tone, tissue distribution, and G-protein activity leads to a better understanding of the potential of the ECS toolkit for therapeutics. The signal transduction pathways examine the modulation of downstream effector proteins, desensitization, signaling cascades, and biased signaling. An in-depth and overall view of the targeted system is achieved through homology modeling where mutagenesis and ligand binding examine the binding site and allow sequence analysis and the formation of libraries for molecular docking and molecular dynamic simulations. Internalization routes exploring receptor-mediated endocytosis and lipid rafts are also considered for explicit signaling. Furthermore, the review highlights nanotechnology and surface modification aspects as a possible future approach for specific targeting.

Endocannabinoid System in the Neuroendocrine Response to Lipopolysaccharide-induced Immune Challenge

The endocannabinoid system plays a key role in the intersection of the nervous, endocrine, and immune systems, regulating not only their functions but also how they interplay with each other. Endogenous ligands, named endocannabinoids, are produced "on demand" to finely regulate the synthesis and secretion of hormones and neurotransmitters, as well as to regulate the production of cytokines and other proinflammatory mediators. It is well known that immune challenges, such as exposure to lipopolysaccharide, the main component of the Gram-negative bacteria cell wall, disrupt not only the hypothalamic-pituitary-adrenal axis but also affects other endocrine systems such as the hypothalamic-pituitary-gonadal axis and the release of oxytocin from the neurohypophysis. Here we explore which actors and molecular mechanisms are involved in these processes.