We’re off to London for a few weeks to celebrate our 50th Wedding Anniversary. As a parting gift to all you lovelorn organic chemists out there, here’s a drug target for a new aphrodisiac.
Yes, it’s yet another G Protein Coupled Receptor (GPCR) of which we have 800+ in our genome, and which some 30% of drugs usable in man target (but not this one).
You can read all about it in a leisurely review of “Affective Touch” in Neuron vol. 82 pp. 737 – 755 ’14, and Nature vol. 493 pp. 669 – 673 ’13. The receptor (if the physiological ligand is known the papers are silent about it) is found on a type of nerve going to hairy skin. It’s called MRGPRB4.
The following has been done in people. Needles were put in a cutaneous nerve, and skin was lightly stroked at rates between 1 and 10 centimeters/second. Some of the nerves respond at very high frequency 50 – 100 impulses/second (50 – 100 Hertz) to this stimulus. Individuals were asked to rate the pleasantness of the sensation produced. The most pleasant sensations produced the highest frequency responses of these nerves.
MRGPRB4 is found on nerves which respond like this (and almost nowhere else as far as is known), so a ligand for it should produce feelings of pleasure. The whole subject of proteins which produce effects when the cell carrying them is mechanically stimulated is fascinating. Much of the work has been done with the hair cells of the ear, which discharge when the hairs are displaced by sound waves. Proteins embedded in the hairs trigger an action potential when disturbed.
Perhaps there is no chemical stimulus for MRGPRB4, just as there isn’t for the hair cells, but even so it’s worth looking for some chemical which does turn on MRGPRB4. Perhaps a natural product already does this, and is in one of the many oils and lotions people apply to themselves. Think of the chemoattractants for bees and other insects.
If you’re the lucky soul who finds such a drug, fame and fortune (and perhaps more) is sure to be yours.
Happy hunting
Back in a few weeks
Chemiotics II 