Figure 4.

Influence of CB₁ receptor (CB₁R) antagonists on the effects elicited by activation of AT₁ receptors (AT₁R). Stimulation of AT₁Rs leads to Ca²⁺-signal generation and rapid biosynthesis of 2-arachidonoylglycerol (2-AG) from diacylglycerols (DAGs) by diacylglycerol lipase (DAGL) activation. If CB₁R and AT₁R activation lead to the same effect, CB₁R antagonism will inhibit the AT₁R-mediated effect, i.e., will decrease blood pressure (BP) and heart rate (HR), gastro-protection, or the chorda tympani response to sweet compounds (upper part of the figure). In the case of opposite effects of CB₁R and AT₁R activation, CB₁R blockade will enhance the AT₁R-mediated effects, i.e., its positive inotropic action, its facilitatory effect on miniature excitatory postsynaptic currents (mEPSCs) or its vasoconstrictor effect (lower part of the figure). For the respective literature, see Table 2 and Section 3.2.1.