Scientists use a wide range of strategies to review the endocannabinoid system (ECS), together with animal analysis. In spite of everything, the ECS is current all through the animal kingdom, the one exceptions being Protozoa (single-celled organisms) and bugs.1 And whereas most animal analysis into ECS operate entails mice, scientists have additionally studied cannabinoids and their receptors in cats2 and canine3 – analysis that would probably profit each people and their pets – and in much less apparent species like sea urchins and sea squirts,4 zebrafish,5 and zebra finches,6 however not zebras as of but.
One key benefit to utilizing mice and rats in biomedical analysis is that through the years biologists have developed widespread behavioral and physiological analogues in these species of innumerable human well being circumstances and illnesses, from melancholy to diabetes. These murine fashions enable researchers to extra simply examine the etiology, or root trigger, of those circumstances in people, and to check and evaluate remedies and interventions for them – for instance, by focusing on the endocannabinoid system.
However there are additionally drawbacks and limitations to mammalian analysis which have led scientists in numerous fields to proceed exploring different animal fashions. In cannabinoid science, just lately revealed research have concerned not solely zebrafish but in addition lobsters and, curiously sufficient, tobacco hornworm caterpillars, which lack CB1 and CB2 cannabinoid receptors.
Zebrafish
A freshwater minnow native to Southeast Asia with slender black and white stripes working the size of its physique, the zebrafish has served as an necessary instrument in human well being analysis because the Eighties – notably for the screening of novel medicine and environmental pollution. The tiny fish develops quickly, reproduces abundantly, and is hardy and simple to take care of, but in addition shares necessary organs, tissues, and genetics with people.7 In the present day, zebrafish are probably the most generally used non-mammalian animal mannequin in toxicology, pharmacology, and behavioral neuroscience analysis89 – together with each psychedelic1011 and cannabinoid science.
On the latter entrance, a just lately revealed paper from researchers in Brazil and England critiques what is thought concerning the zebrafish endocannabinoid system and its potential to help the research of hashish results in people.12 Printed within the journal Laboratory Animal Analysis in February 2022, the article concludes that the zebrafish mannequin provides quite a few strengths in cannabinoid analysis, together with many similarities to the human system; an embryonic stage that reduces the necessity for in vivo (in reside animal) exams, in keeping with worldwide moral laws; and the chance to conduct research in much less time and at decrease value.
Two further latest research illustrate its use within the discipline. One revealed by a workforce of Italian researchers in Prescription drugs in November 2021 discovered {that a} full-spectrum hashish extract was not poisonous to zebrafish larvae, didn’t have an effect on embryo growth and survival, and elevated embryo locomotion at excessive doses.13
In one other, revealed in Developmental Neuroscience final month, researchers with the College of Alberta noticed the expression of six key receptors that endocannabinoids bind to – CB1, CB2, TRPV1, TRPA1A, TRPA1B, and GPR55 – in creating zebrafish embryos throughout a timeline roughly equal to the primary two to 10 weeks of human embryonic growth. “This work goals to function a basis for additional investigation on the position of cannabinoid and cannabinoid-interacting receptors in early embryonic growth,” the authors write.
Lobster
Right here’s an fascinating one out of the esteemed College of California, San Diego, Scripps Analysis Institute. “Regardless of an extended historical past of use in synaptic physiology, the lobster has been a uncared for mannequin for behavioral pharmacology,” the authors write. So the place to start out? Maybe by evaluating a Maine restaurateur’s considerably notorious 2018 declare that hashish smoke may ease lobsters’ struggling. As defined in a June 2021 article within the Portland (Maine) Press Herald, the UCSD researchers determined to place this to the take a look at by first figuring out if lobster gill respiration in air would lead to important THC uptake, after which measuring whether or not this could have any detectable behavioral results – particularly those who may mirror diminished ache or stress.
Certain sufficient, in keeping with outcomes revealed in Pharmacology Biochemistry and Conduct 14 in August 2021, publicity to THC vapor from an digital vape cartridge produced dose-dependent ranges of the intoxicating cannabinoid in all lobster tissues examined. After half-hour it additionally decreased locomotor exercise within the animals. However when testing how 60 minutes of THC publicity impacted lobsters’ bodily response to partial immersion in heat or sizzling water, the researchers discovered solely minimal impact – which means the declare that hashish meaningfully reduces their sensation of ache stays as but unfounded.
Tobacco Hornworm
Lastly, and maybe most curiously of all on condition that bugs don’t have cannabinoid receptors, a paper revealed late final yr within the Journal of Visualized Experiments (JoVE) presents the tobacco hornworm as a novel insect mannequin for pre-clinical cannabinoid research.15
The authors start by noting that whereas these giant moth larvae lack CB1 and CB2 receptors, they nonetheless possess different receptors able to interacting with cannabinoids, notably CBD, which is thought for binding with a variety of receptors past the basic cannabinoid receptors. “The [insect] mannequin system offers a helpful instrument to grasp pharmacological roles of cannabinoids by a cannabinoid receptor-independent method,” they clarify.
In a earlier paper within the journal Nature Scientific Experiences,16 the identical authors confirmed that tobacco hornworm caterpillars, thought-about a significant pest on tobacco and tomato crops, most well-liked low-CBD over high-CBD hashish vegetation, supporting the speculation that hashish produces the compound no less than partly to guard itself from insect herbivores.
The brand new paper outlines a analysis protocol for additional CBD feeding research with tobacco hornworms. “The comparatively brief life cycles allow researchers to review the influence of cannabinoid remedies over a number of generations of a homogenous inhabitants,” the authors write, “permitting for information to help an experimental design in larger mammal mannequin organisms.”
Nate Seltenrich, an unbiased science journalist primarily based within the San Francisco Bay Space, covers a variety of topics together with environmental well being, neuroscience, and pharmacology.
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