Texon
Member
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- Nov 28, 2016
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I would also add all of the ergot-derivative drugs here as well. They are all histamine antagonists on their own.
Striking differences of action of lisuride stereoisomers at histamine H1 receptors. - PubMed - NCBI
"...High affinity of 8S-lisuride and low affinity of 8R-lisuride was also estimated for gpH(1)Rs and hH(1)Rs in radioligand binding studies. The 1-allylated derivative of 8S-lisuride, 1-allyl-8S-lisuride, was equipotent with its parent compound (pD(2) 7.7) and showed enhanced efficacy in guinea pig ileum and at recombinant gpH(1)Rs in GTPase studies (E (max) 53%, 32%). Other antiparkinsionian drugs such as 8S-terguride, pergolide, cabergoline and bromocriptine displayed lower affinities for H(1)Rs than 8S-lisuride. In conclusion, our results show that the antiparkinsonian drug 8S-lisuride is dramatically more potent than its epimeric counterpart 8R-lisuride in all assays used. 8S-Lisuride behaved as a partial agonist at gpH(1)Rs and as a silent antagonist at hH(1)Rs. Thus 8S-lisuride may act as an antagonist in vivo. This may be of potential importance since H(1)Rs modulate dopaminergic transmission in the brain."
Brain-mediated protective interactions of histaminergic H2 and dopaminergic systems in rats. - PubMed - NCBI
"...Pretreatment with dopamine agonists (bromocriptine 2.5, L-dopa 2.5, apomorphine 0.05 mg/kg i.p.) and a histamine H2 receptor antagonist (cimetidine 50.0 mg/kg i.p.) was found to greatly reduce the haemorrhagic gastric lesions induced by 15-min pylorus ligation in rats. On the other hand, pretreatment with dopamine antagonists (haloperidol 5.0, sulpiride 1.0, domperidone 5.0 mg/kg i.p.) significantly aggravated these lesions. Cimetidine markedly diminished the ulcerogenic effect of haloperidol but not that of domperidone, suggesting a brain-mediated site for the protective interaction of cimetidine and dopamine systems."
The second study above suggests that dopaminergic drugs are H2 antagonists, or H2 antagonists are dopaminergic, or both. This matches my previous post showing that dopaminergic drugs are even more potent than H2 antagonists as gastro-protectants.
Dopaminergic drugs treat ulcers better than acid-blockers | Ray Peat Forum
Does this include bergamot as in earl grey tea? Or is there no connection whatsoever?