Marijuana receptor gene cloned

Article Abstract:

Scientists have been looking for the cellular receptor which binds tetrahydrocannabinol (THC), the active ingredient in marijuana, for the past 25 years. Cannabinoids, including THC, specifically inhibit an enzyme, adenylate cyclase, which is involved in the intracellular transmission of a signal generated by the binding of a substance to a receptor. Therefore, it was known that a specific receptor for THC existed, rather than a nonspecific absorption of THC onto the cell membrane. A group of scientists from the National Institute of Mental Health have identified and characterized the gene that codes for the receptor. Their findings are reported in the August 9, 1990 issue of the journal Nature. The scientists discovered the gene when they were looking for genes encoding receptors that bind peptides that transmit pain signals, such as the receptor for substance P and neuromedin. The receptor for cannabinoids was characterized when the gene that was isolated was put into cells that can synthesize the protein receptor, and the receptor bound cannabinoids and caused inhibition of adenylate cyclase. The characterization of the gene coding for the marijuana receptor will lead to further understanding of how the brain functions. Natural substances that bind to the receptor can now be identified. These substances can act as marijuana does, modulating pain, learning, memory, and producing other effects. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, Tetrahydrocannabinol

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Key piece found for immunology puzzle?

Article Abstract:

A recent discovery may solve a puzzle that immunologists have worked on for over 10 years. Once a foreign substance such as a virus enters the body, the immune system manufactures antibodies (proteins that fight specific infections) that will attack the virus the next time it is encountered. The immune system can create a huge number of antibodies, each specific to only one infectious agent. In the 1970s, researchers discovered that the genes which direct the manufacture of antibody proteins originate from separate locations along the DNA (deoxyribonucleic acid) molecule. This led them to look for the enzyme responsible for linking the segments of DNA that make up an antibody gene. Researchers have now found a gene that may code for this key enzyme; it has been named recombinase. Research into this enzyme is important because, without recombinase, the immune function would break down. Recombinase is vital to the development of B cells, which produce antibodies, and T cells, which kill cells that have been infected by viruses. An abnormality in the recombinase system could be responsible for inherited immunological diseases where patients must be protected from any and all germs; in these rare diseases contact with one infectious organism could be fatal. (Consumer Summary produced by Reliance Medical Information, Inc.)

Antibody diversity, Human immunogenetics

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Leishmania susceptibility puzzle gets another twist

Article Abstract:

Nancy Noben-Trauth found that knocking out the gene for IL-4, which produces an inappropriate Th2 immune defense, did not make mice any less susceptible to Leishmania. Work by Kenneth Murphy suggests that susceptibility could be caused by an inadequate response to IL-12, and thus a failed Th1 response.

Interleukins, Immune response, Disease susceptibility, Leishmaniasis

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