Serotonin-induced alterations in inositol phospholipid metabolism in human platelets

Serotonin receptors in platelets of bipolar and schizoaffective patients: effect of lithium treatment

“…The pharmacological characteristics of 5HT 2A receptors in brain and platelets appear to be similar (Elliott and Kent 1989;Ostrowitzki et al 1993), as both brain and platelet 5HT 2A receptors have been linked to the phosphoinositide signaling system (deChaffoy de Courcelles et al 1987). Also, the nucleotide sequence of human platelet 5HT 2A cDNA is identical to that of the (Cook et al 1994).…”

“…Platelets possess functionally active 5HT 2A receptors linked to the phosphoinositide signaling system (deChaffoy de Courcelles et al 1987), and their activation results in a change of shape and the aggregation of platelets (Peters and Grahame-Smith 1980;Geaney et al 1984). Several investigators have reported that 5HT 2A receptors are increased in the platelets of depressed patients when compared with normal controls, and this increase is correlated with the severity of depression (Biegon et al 1987;Pandey et al 1990;Mendelson 2000).…”

Platelet Serotonergic Predictors of Clinical Improvement in Obsessive Compulsive Disorder

“…4,5,11 We report for the first time that OCD patients have an elevated platelet IP 3 content with unchanged 5-HT 2A binding at baseline. 5-HT 2A receptors 42 are mainly coupled to the phosphoinositide signaling system. An increase in the intrinsic activity of the 5-HT 2A receptors in untreated OCD patients may account for this result, in the absence of an increase in receptor number (the Bmax and Kd of the 5HT 2A receptor measured with [ 125 I]-LSD did not differ from those of the controls).…”

Co-activation of Gi and Gq proteins exerts synergistic effect on human platelet aggregation through activation of phospholipase C and Ca2+ signalling pathways

“…Receptors for 5-HT in platelets are coupled with Gq/ PLC (De Chaffoy de Courcelles et al, 1987;Martin, 1994) whereas epinephrine interacts with α 2 -a d r e n o c e p t o r s coupled with Gi/adenylyl cyclase pathway (Steen et al ., 1993). Recent studies show that β γ-subunits of activated Gi protein can also activate PLC (Clapham and Neer, 1997;Banno et al, 1998).…”