Neurotransmitter receptors serotonergic system

Several psychological disorders are currently being discussed in terms of the effect of the physical state of the membrane lipids on neurotransmitter receptor function. Hibbeln and Salem (1995) suggest that serotonin levels and membrane 22 6n-3 content are directly linked, whereby low 22 6n-3 yields low serotonin. This results in an individual being susceptible to depression or other affective diseases. These authors suggest that the depletion of 22 6n-3 induces a change in membrane physical properties, which, in turn, influences the function of either serotonergic receptors or serotonin reuptake systems. 

Histamine was found to be a neurotransmitter in the brain in 1982, by T. Watanabe from Tohoku University and H. Wada from Osaka University. It was associated with a presynaptic receptor, with methyl histamine acting as an agonist, and thioperamide as an antagonist. The histaminergic neuronal system has the same distribution in the body as the noradrenergic and serotonergic systems, and it is involved in memory, emotions, and behavior. No disease has yet been found to be due to a disturbance of the histaminergic neuronal system. 

In rodents, PCP produces not only ataxia, but also stereotyped behavior and hyperactivity. The PCP-induced stereotyped behavior is thought to be due to changes in serotonergic and dopaminergic systems (Nabeshima et al. 1983 Martin et al. 1979 Sturgeon et al. 1981). It is not known whether PCP receptors mediate PCP-induced hyperactivity or stereotyped behavior or even the effect on neurotransmitter systems. It is also possible that mu, kappa, or sigma opioid receptors are involved (Castellani et al. 1982). 

Murphy, D.L., Andrews, A.M., Wichems, C.H., Li, Q., Tohda, M., and Greenberg, B. (1998) Brain serotonin neurotransmission an overview and update with an emphasis on serotonin subsystem heterogeneity, multiple receptors, interactions with other neurotransmitter systems, and consequent implications for understanding the actions of serotonergic drugs. J Clin Psychiatry 59 5uppl 15 4-12. 

---