G protein activation represents an early key event in the complex GPCR signal transduction process and is usually studied by label-dependent methods targeting specific molecular events. However, the constrained environment of such "invasive" techniques could interfere with biological processes. Although histamine receptors (HRs) represent (evolving) drug targets, their signal transduction is not fully understood. To address this issue, we established a non-invasive dynamic mass redistribution (DMR) assay for the human H(1-4)Rs expressed in HEK cells, showing excellent signal-to-background ratios above 100 for histamine (HIS) and higher than 24 for inverse agonists with pEC(50) values consistent with literature. Taking advantage of the integrative nature of the DMR assay, the involvement of endogenous G alpha(q/11), G alpha(s), G alpha(12/13) and G beta gamma proteins was explored, pursuing a two-pronged approach, namely that of classical pharmacology (G protein modulators) and that of molecular biology (G alpha knock-out HEK cells). We showed that signal transduction of hH(1-4)Rs occurred mainly, but not exclusively, via their canonical G alpha proteins. For example, in addition to G alpha(i/o), the G alpha(q/11) protein was proven to contribute to the DMR response of hH(3,4)Rs. Moreover, the G alpha(12/13) was identified to be involved in the hH(2)R mediated signaling pathway. These results are considered as a basis for future investigations on the (patho)physiological role and the pharmacological potential of H(1-4)Rs.