Effects of drugs interfering with the metabolism of octopamine on blood pressure of rats.
1. p-Octopamine injected in lateral ventricle of conscious spontaneously hypertensive rats decreased systolic blood pressure (SBP). 2. Precursors of octopamine--tyrosine, tyramine and phenylethanolamine (PEA)--had the same effect. The administration of pargyline, a MAO inhibitor, which increased brain octopamine, resulted in a reduction of systolic blood pressure; and this decrease was greater after administration of octopamine precursors and PEA. 3. Similarly, drugs known to inhibit activity of phenylethanolamine N-methyl-transferase (PNMT) and to increase brain octopamine level such as SKF 64139 and DCMB decreased SBP. 4. p-Octopamine hypotension was not antagonized by piperoxan, yohimbine and prazosin, a relatively selective antagonist of post-synaptic alpha adrenoceptors. 5. These results suggest that octopamine may be involved in central blood pressure regulation, and the receptors sensitive to octopamine appeared to be distinct from those receptive to the catecholamines.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004983:Ethanolamines / Q000494:pharmacology; D006358:Hot Temperature; D008297:Male; D009655:Octopamine / Q000378:metabolism*; D010293:Pargyline / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D004983:Ethanolamines; D009655:Octopamine; C005332:N-phenylethanolamine; D010293:Pargyline; D011224:Prazosin