The G- protein coupled receptors (GPCRs) include a group of receptors that still undergoes intense research. Such research occurs at both academic levels and in the pharmaceutical industry. Several advancements occurred recently in the structure of the G- protein coupled receptors. There appeared new crystal structures as well as ground states and active states. Such advancements in the structure of these proteins helped in the further understanding of the receptors especially in the therapeutic fields. It also possesses an immense impact on the GPCR field (Andrew, 2008, pp.6).
Several fundamental factors help in the understanding of these receptors. Such factors include crystallization. Crystallization presents a static ‘snap- shot’ of these dynamic proteins. Other vital factors include the synergistic approaches of biophysics, molecular modeling, protein chemistry, and pharmacology and cell biology. The crucial receptor functions addressed include ligand-binding, receptor activation coupling to effectors and resultant signaling mechanisms and receptor trafficking. (Jackson, 2000, pp. 45- 56)
Receptors normally exist in families. The G protein- coupled receptors get localized and clustered on the cell membrane by means of the photo- activated localization microscopy (PALM). Further research on the different structures and structural characteristics continue. More scientists discovered the structural differences that exist between the G- proteins coupled receptors and other receptors.
The G- protein coupled receptors include the largest protein family that exists. These receptors can also be termed as seven membrane receptors, 7TM receptors and heptahelical receptors. In addition to that, these receptors include a protein family of transmembrane receptors. These receptors tend to transducer an extracellular signal (ligand binding) into an intracellular signal, which eventually leads to the G- protein activation. The G- protein family comprises of between 600 and 1000 members. All these members take part in numerous kinds of stimulus- response pathways. (Ravi, 2002, pp. 96- 98).
The G- protein coupled receptors possess numerous functions especially in the recognition of a wide range of ligands. These include photons, small molecules and proteins. The G- protein coupled receptors are connected to numerous normal pathological and biological conditions. Moreover, approximately 45% of the modern medical drugs tend to affect this target class of receptors.
Despite the fact that these receptors possess many functions in cell biology, scientists still, find it challenging in understanding them better. For better understanding of these proteins, scientists need to carry out more researches. One of the fundamental challenges facing scientists who are interested in finding out the functioning characteristics of the receptors includes the model mode of the particular receptor in question. Researchers tend to base their focus on all details including the structure and functions of the GPCRs to RNA editing. Moreover, others carry out splicing to signaling through the G- protein and downstream messenger system to interaction of receptors with the accessory proteins.
Numerous functions of the G- protein coupled receptors have surfaced with continuous researches carried out by scientists. All the researches occur with a main aim of better understanding the structure and functions of these receptors. Structurally, it occurs that the G- protein receptors occur in different forms. As earlier noted, these receptors normally occur in crystal states, presenting a static ‘snap- shot’ of these dynamic proteins. In addition, these receptors occur as the largest family of proteins with most members performing many kinds of stimulus- response pathways. Moreover, the G- protein coupled receptors get localized and clustered on the cell membrane by means of a photo- activated localization microscopy (PALM).
These proteins come in different terminologies. They can be termed in different scientific names. For instance, seven membrane receptors, G- protein linked receptors, 7TM receptors and heptahelical receptors.
The different and numerous functions of these receptors tend to emphasize their significance in fields such as cell biology, protein chemistry, biophysics molecular modeling and pharmacology. Some of the main functions of these receptors include ligand binding that involves the transducing of extracellular signals. Another function of the receptors includes the receptor activation. Next functions include coupling to effectors and resultant signaling mechanisms. Finally, these receptors work on receptor trafficking.
Several crucial factors enable scientists to understand the G- protein coupled receptors better. First, there includes the factor crystallization that presents a static snap shot of the dynamic proteins. Other factors include synergetic approaches of biophysics, cell biology among others. These proteins appear linked to many normal pathological and biological conditions. Furthermore, a relatively good percentage of medicinal drugs affect this target class.
Another fundamental scientific receptor includes the menthol taste receptor. It possesses several different characteristics to the G- protein coupled receptors. The menthol receptors include a cold type of receptor. The human sensory system possesses a large capability of sensing the alterations in temperature. This occurs as a result of coordination of thermo sensory neurons. At the stage where the prime afferent nerve exists, where thermal stimuli get turned into neuronal bustle, the temperature- sensitive members of the TRP channel exist. These channels tend to respond to an extensive range of temperatures. These temperatures may range from humid to extremely hot, or cool to very cold. Most of these conduits occur as receptors for ligands that extract discrete psychophysical ambiance. These sensations may include heat that comes with capsaicin and the resultant cold that one feels with the menthol. Similar to the G- protein receptors, numerous advancements occurred in the cold and menthol receptors. Scientists still carry out extensive researches on these receptors. This extensive research occurs in order to enhance the understanding of their functional and structural characteristics (James, 2012, pp78).
Majority of cold sensitive neurons appear responsive to the omnipresent cooling compound menthol. Menthol includes a recurring terpene alcohol that exists in mint leaves. Judicious deliberations of the menthol tend to bring a pleasant and cool sensation. This occurs as the similar sensation that one feels when consuming menthol products like vapor- rubs and candy. However, it appears that when the menthol gets utilized in higher quantities, it may cause some adverse impacts on the consumer or user. These impacts may appear as noxious that lead to irritation, burning sensations and pain. Studies carried out by two scientists, Hensel and Zotterman, show that in the 1950s, the menthol elicited itself. This occurred since it increased its threshold temperatures for the activation of the cold receptors. However, the hypothesis of these two scientists took about five decades to be proven.
Menthol tends to stimulate taste in humans through different gustatory nerves. It tends to produce some amount of bitterness at the back of the tongue. Several experiments occurred to verify the intensity of the menthol on the neurons. Various laboratory experiments occurred in order to investigate the impacts and characteristics of the menthol. To achieve this, scientists carried out comparative tests between menthol and capsaicin. In addition, the comparisons occurred with an aim of finding out the taste of both menthol and capsaicin. Eventually, it occurred that menthol possesses a bitter taste when it is applied on some areas of the tongue.
The menthol also possesses exclusively cold sensation when applied on the circumvallated papillae. Moreover, it comes with a burning feeling just as well as the capsaicin. This burning sensation is normally felt on the fungi form region of the tongue. Experimentally, the menthol brings a sense of bitterness in the circumvallated regions. However, there occurs an equal level of burning on the other three regions of the tongue.
With more researches, the functional and structural characteristics of the menthol will eventually surface. The intensity of bitterness as well as burning in this receptor still undergoes numerous researches. In addition, the differences in intensity of other chemicals compared to that of menthol helps researches in verifying the exact quantitative levels of burning and bitterness. Thus, there still exist chemicals with higher levels of bitterness and burning as compared to menthol (Donald, 2001, pp93- 102).
Therefore, it occurs clearly that the contrast between the G- proteins coupled receptors and the menthol receptors appear distinct. Both the structures and functions of these receptors differ immensely. Moreover, the factors that affect their functioning also tend to differ. For instance, the activities of the menthol are largely affected by the changes in temperature. With a relative reduction in the temperatures, the cooling sensation of the menthol rises. In addition, when the menthol is used, it leads to noxious that causes irritation, burning and pain (John, 1995, pp 56- 72).
On the other hand, factors that affect the G- proteins coupled receptors include the synergetic approaches of biophysics, molecular modeling, and protein chemistry. Other factors that possess impacts on the GPCRs include pharmacology and cell biology.
In conclusion, it occurs vital to understand how these different receptors work. The knowledge of their functional and structural characteristics occurs as a crucial scientific factor. As such, this has led to the continuous investigations by different scientists in order to verify these characteristics (Bruce, 2008, pp 32- 45). Although numerous hypotheses made by several scientists have been proven with recent and past researches, more scientists still venture into the study to find out more. These constant investigations help individuals in both academic levels and pharmaceutical fields understand the functional and structural characteristics of these receptors in a better and advanced way.
Both the G- protein coupled receptors and the menthol receptors possess distinct characteristics. These characteristics differ from both structural and functional characteristics. In this essay, it appears clearly that the G- protein coupled receptors possess numerous functions than the menthol receptors. Some of the functions of the g- protein coupled receptors include recognition of a wide range of ligands such as photons, small molecules and proteins. In addition, these proteins are connected to a wide range of biological and pathological conditions. About 45% of the modern medical drugs affect this target class of receptors.
The G- protein coupled receptors occur in a wide family of proteins. This family consists between from 600 and 1000 members. Furthermore, all these members participate in several types of stimulus- response pathways.
The menthol taste receptor also includes another scientifically fundamental receptor. The menthol receptor tends to stimulate taste through different gustatory nerves. Moreover, it produces some level of bitterness behind the tongue. It produces a painful and burning sensation when consumed in large quantities.
These two receptors occur fundamental in both academic levels and pharmaceutical fields. However, further researches on their structural and functional characteristics continue to take place.
References
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