Apr 1, 1976

Effects of alpha-adrenoceptor agonists and antagonists on pre- and postsynaptically located alpha-adrenoceptors

European Journal of Pharmacology
G M Drew


The effects of alpha adrenoceptor agonists and antagonists have been examined at pre- and post-synaptically located alpha-adrenoceptors in the pithed rat. The presynaptic receptors were those located at the cardiac sympathetic nerve terminals and the postsynaptic receptors were those present in vascular smooth muscle. Clonidine was approximately equipotent at pre- and post-synaptic alpha-adrenoceptors, whilst LSD and BAY-1470 were more active at the pre- than at post-synaptic sites. Oxymetazoline, naphazoline, methoxamine and phenylephrine were all much more active at the postsynaptic alpha-adrenoceptors. Phentolamine was the most potent antagonist at both pre- and post-synaptic alpha-adrenoceptors. Piperoxan, yohimbine and tolazoline were about 3-7X less potent than phentolamine at both sites. Thymoxamine was about 10X less potent than phentolamine at postsynaptic alpha-adrenoceptors but about 1000X less active at the presynaptic receptors. The differential actions of both agonsists and antagonists at pre- and post-synaptic alpha-adrenoceptors suggest that the receptors may be of different types.

  • References15
  • Citations143

Mentioned in this Paper

Diastolic Blood Pressure
Adrenergic alpha-Agonists
Adrenergic alpha-Antagonists
Norepinephrine Receptors
Rats, Laboratory
Pulse Rate

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

LRRK2 & Immunity During Infection

Mutations in the LRRK2 gene are a risk-factor for developing Parkinson’s disease. However, LRRK2 has been shown to function as a central regulator of vesicular trafficking, infection, immunity, and inflammation. Here is the latest research on the role of this kinase on immunity during infection.

Antiphospholipid Syndrome

Antiphospholipid syndrome or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by the presence of antibodies directed against phospholipids.

Meningococcal Myelitis

Meningococcal myelitis is characterized by inflammation and myelin damage to the meninges and spinal cord. Discover the latest research on meningococcal myelitis here.

Alzheimer's Disease: MS4A

Variants within membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated in Alzheimer's disease by recent genome-wide association studies. Here is the latest research.