Opiates and cannabinoids affect sperm motility

Scientists at the University of the Basque Country have proved the existence of opiate and cannabinoid receptors on human spermatozoa, as well as the fact that the activity of these receptors affects the mobility of these cells.

Before getting the ability to fertilize an egg, young spermatozoa must go through several stages of maturation. The changes observed in this case are partly due to the receptors of the cell surface, which include opiate and cannabinoid receptors.

It is known that the use of external opiates (heroin, methadone) reduces sperm motility, and external cannabinoids (hashish) – disrupts the reproductive process. At the same time, the body itself synthesizes internal opiates and cannabinoids that help to tolerate stress and pain and also take part in reproduction.

However, despite all the known facts, there was still a significant lack of information about the expression of opiate and cannabinoid receptors on human spermatozoa and their effect on cell motility and activity.

Using a set of techniques, the authors found three types of opiate receptors (delta, kappa and mu) and two types of cannabinoid receptors (CB1 and CB2) on the surface of human spermatozoa. Moreover, receptors of all types are found on the head, middle part and tail of spermatozoa.

These receptors work according to the "key-lock" principle, while a receptor acts as a lock, with which a key suitable only for it interacts. There are two types of such keys: agonists that activate certain processes in the cell, and antagonists that connect to the "lock", but do not open it, thus ensuring the blocking of the receptor.

To study these processes, scientists incubated human spermatozoa with synthetic agonists and antagonists of the receptors of interest to them. As a result, they found that in order to maintain sperm motility, the activity of a minimum number of opiate delta receptors is necessary. At the same time, the activation of opiate mu receptors suppresses cell motility, and kappa receptors are involved in a process that has nothing to do with sperm motility.

As for the cannabinoid system, activation of CB1 and CB2 receptors leads to a decrease in the fraction of spermatozoa capable of the fastest progressive movement. At the same time, activation of CB1 receptors increases the number of slow–moving spermatozoa, and activation of CB2 receptors increases the number of cells with progressive but slow movement.

Opiates and cannabinoids are known to regulate reproductive function through the activity of the central nervous system. The results obtained by the authors indicate that this regulation is also carried out by changing the activity of receptors directly on the surface of sperm. Thus, the type and concentration of internal opiates and cannabinoids affecting sperm cells on their way to the egg affects their mobility.

The obtained results provide new opportunities for the diagnosis and treatment of many pathologies. For example, the analysis of the components of the system of opiate and cannabinoid receptors will help to better understand the problems of infertility of unclear etiology. In addition, it is possible to create drugs for the treatment of infertility based on agonists or antagonists of the corresponding receptors.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily

23.06.2008