The different pharmacological syndromes produced by morphine and related drugs in the chronic spinal dog led Martin and his colleagues (1,2) to suggest that these drugs exert their agonist actions 0y interacting with three distinct receptors (~,K, and e). Morphine was hypothesized to be an agonist for the p receptor, ketazocine (ketocyclazocine) was an agonist for the K receptor, and SKF-10,0q7...

Agonist efficacy is a measure of how well an agonist can stimulate a response system linked to a receptor. Efficacy can be assessed in functional assays and various parameters (E(max), K(A)/EC(50), E(max).K(A)/EC(50)) determined. The E(max).K(A)/EC(50) parameter provides a good estimate of efficacy across the full range of efficacy. A convenient assay for the efficacy of agonists for some recep...

This paper looks at ion channels as an example of the pharmacologist's stock in trade, the action of an agonist on a receptor to produce a response. Looked at in this way, ion channels have been helpful because they are still the only system which is simple enough for quantitative investigation of transduction mechanisms. A short history is given of attempts to elucidate what happens between th...

5-HT(2A) serotonin receptors are unusual among G-protein coupled receptors in that they can be internalized and desensitized, in some cell types, in an arrestin-independent manner. The molecular basis of the arrestin-insensitivity of 5-HT(2A) receptors is unknown but is probably caused, in part, by the apparent lack of agonist-induced 5-HT(2A) receptor phosphorylation. Because the arrestin-inse...

In this study, the relationship between high-affinity agonist binding and second messenger production was examined at native and mutant 5-hydroxytryptamine2A receptors. At native 5-hydroxytryptamine2A receptors all agonists, with the exception of quipazine, discriminated between high- and low-affinity states of the receptor, as determined by analysis of competition binding assays. There was no ...

Background: Functional activities mostly done in daily life such as jumping, walking, running, and stairs ascending-descending require dynamic stability of the knee. The knee joint is required to have effective efficient functional avoid injury when performing them. It can be achieved by increasing muscle strength through strengthening exercises with aim balancing agonist muscles (quadriceps fe...

introduction: estrogen and progesterone are supposed to modify pain sensitivity. however, the actual role of each of these steroid hormones in this respect is not well known. plasma concentrations of these hormones show variation during estrous cycle. the role of alpha2 receptors in tonic pain has been pointed out. the aim of the present study was to investigate the agonist and antagonist effec...

adenosine has many of the characteristics of a regulator of cerebral blood flow and adenosine receptors change in morphine dependency. in this study the changes in adenosine receptors' responsiveness of pial vessels in the hind limb area of the sensory cortex were evaluated in morphine dependent rats (mdr) using the laser doppler flowmetry technique. adult male sprague dawley rats (250-350...

introduction mild intermittent asthma is common in children and viral infections are responsible for the majority of exacerbations. as leukotrienes are potent inflammatory mediators, some studies have shown that montelukast, a leukotriene receptor antagonist, may be effective on reduction of asthma symptom. to determine whether a short course of montelukast in asthmatic children with common col...