Male and Female Rats Differ in Brain Cannabinoid CB1 Receptor Density and Function and in Behavioural Traits Predisposing to Drug Addiction- Effect of Ovarian Hormones
A recent study has revealed that cannabinoid receptor 1 (CB1) density and function depend on sex and hormone levels. Researchers have found that the effects of CB1 receptors in brain regions of female rats caused them to engage in behaviors that are associated with a higher risk for substance abuse disorders. Interestingly, female rats reported a lower density of CB1 receptors, suggesting that an increase in cannabis receptors may improve rats’ chances of developing a substance use disorder. Further studies need to be conducted in order to test the validity of these findings for human mammals considering the differences between the human and rat cannabinoid systems.
This study highlights the inconsistency between rat and human endocannabinoid systems. Rat models are commonly used to study biological processes for ethical, efficient, and economic reasons, but they are not always appropriate. Previous studies featured on this blog have reported fundamental differences in the endocannabinoid systems of rats and humans, suggesting that they may not provide valid evidence. Non-human mammalian models such as monkeys may provide more valid results when looking into the therapeutic effects of cannabinoids or interactions between opioid and cannabinoid systems.
The study is available for review or download here
Pre- and postnatal tobacco and cannabis exposure and child behavior problems: Bidirectional associations, joint effects, and sex differences
Prenatal maternal cannabis and tobacco use is predictive of behavioral problems among toddlers. Resulting differences from control groups include anxiety, depression, and attention problems. Female children of mom’s consuming substances, in particular, seem to be more susceptible to problems relating to internalization, attention, and sleep. Additionally, the behavioral problems induced by prenatal cannabis and tobacco consumption often lead to further maternal substance consumption, which frequently exacerbates existing behavioral problems.
Impacts of cannabinoid epigenetics on human development- reflections on Murphy et. al. ‘cannabinoid exposure and altered DNA methylation in rat and human sperm’ epigenetics
An op-ed has praised the work published last year which exposed how pre-conception exposure to cannabis in males is related to alterations in epigenetic regulation of the central nervous and immune systems. Murphy et. al.’s paper ‘Cannabinoid exposure and altered DNA methylation in rat and human sperm,’ revealed that the sperm cells of men who have consumed cannabis are a key vector that may affect neuraxis, heart blood vessels, immune stimulation, secondary genomic instability, and carcinogenesis in the fetus offspring. The author of the response piece extrapolates the data collected by Murphy et. al. to conclude the genome-epigenome is extremely sensitive to environmental toxicants and that further research should examine the epigenomic toxicology of multiple cannabinoids.
The effect of prenatal exposure to cannabis on birth rates, birth outcomes, and the health of the mother is still uncertain. Studies focussing on cannabis use during pregnancy are limited, and what little has been reported, is inconsistent. The featured article now brings to light that bothparents may need to be cautious when attempting to conceive or when having unprotected sex as cannabis may affect both germ cells. Currently, governing bodies of obstetricians advise that pregnant mothers cease any cannabis use so if someone who needs cannabis for a medical purpose that improves their quality of life becomes pregnant they need to seek out alternative methods of treatment. Research is needed so that pregnant women can safely continue their medication or so that alternatives can be found so that women do not need to suffer for the duration of their pregnancy and possible breastfeeding period.