Question

this question is related to pharmacology

Briefly describe each of the 3 general approaches to study differences in agonists including: 1) choice of response pathway, 2) augmentation/modulation of stimulus pathway, or 3) manipulation of receptor density.

Answer 1

1) Reaction time. n. ... Simple reaction time applies when there is only one possible stimulus requiring only one type ofresponse; choice reaction time (CRT) when there are two or more possible stimuli requiring different responses” (Coleman 2001).

2) The insulin secretory response by pancreatic β-cells to an acute “square wave” stimulation by glucose is characterized by a first phase that occurs promptly after exposure to glucose, followed by a decrease to a nadir, and a prolonged second phase. The first phase of release is due to the ATP-sensitive K+ (KATP) channel-dependent (triggering) pathway that increases [Ca2+]i and has been thought to discharge the granules from a “readily releasable pool.” It follows that the second phase entails the preparation of granules for release, perhaps including translocation and priming for fusion competency before exocytosis. The pathways responsible for the second phase include the K ATP channel-dependent pathway because of the need for elevated [Ca2+]i and additional signals from K ATP channel-independent pathways. The mechanisms underlying these additional signals are unknown. Current hypotheses include increased cytosolic long-chain acyl-CoA, the pyruvate-malate shuttle, glutamate export from mitochondria, and an increased ATP/ADP ratio. In mouse islets, the β-cell contains some 13,000 granules, of which ∼100 are in a “readily releasable” pool. Rates of granule release are slow, e.g., one every 3 s, even at the peak of the first phase of glucose-stimulated release. As both phases of glucose-stimulated insulin secretion can be enhanced by agents such as glucagon-like peptide 1, which increases cyclic AMP levels and protein kinase A activity, or acetylcholine, which increases diacylglycerol levels and protein kinase C activity, a single “readily releasable pool” hypothesis is an inadequate explanation for insulin secretion. Multiple pools available for rapid release or rapid conversion of granules to a rapidly releasable state are required.
Our knowledge of the mechanisms involved in stimulus-secretion coupling in the pancreatic β-cell has increased remarkably in the last 10–15 years. In 1984, the ATP-sensitive K+ (KATP) channel was identified and found to be responsible for glucose-induced depolarization of the β-cell. Closure of this channel increases Ca2+ entry and [Ca2+]and thereby stimulates insulin release.

3) The act of crushing tablets or opening capsules, which are not designed to be administered in this way, alters the formulation of the medication and potentially can have serious negative consequences for the patient.