Effects
cGMP is a common regulator of ion channel conductance, glycogenolysis, and cellular apoptosis. It also relaxes smooth muscle tissues. In blood vessels, relaxation of vascular smooth muscles lead to vasodilation and increased blood flow.
cGMP is a secondary messenger in phototransduction in the eye. In the photoreceptors of the mammalian eye, the presence of light activates phosphodiesterase, which degrades cGMP. The sodium ion channels in photoreceptors are cGMP-gated, so degradation of cGMP causes sodium channels to close, which leads to the hyperpolarization of the photoreceptor's plasma membrane and ultimately to visual information being sent to the brain. GMP and a number of its derivatives also have an umami taste.
cGMP is also seen to mediate the switching on of the attraction of apical dendrites of pyramidal cells in cortical layer V towards semaphorin-3A (Sema3a). Whereas the axons of pyramidal cells are repelled by Sema3a, the apical dendrites are attracted to it. The attraction is mediated by the increased levels of soluble guanylate cyclase (SGC) that are present in the apical dendrites. SGC generates cGMP, leading to a sequence of chemical activations that result in the attraction towards Sema3a. The absence of SGC in the axon causes the repulsion from Sema3a. This strategy ensures the structural polarization of pyramidal neurons and takes place in embryonic development.
cGMP, like cAMP, gets synthesized when olfactory receptors receive odorous input. cGMP is produced slowly and has a more sustained life than cAMP, which has implicated it in long-term cellular responses to odor stimulation, such as long-term potentiation cGMP in the olfactory is synthesized by both membrane guanylyl cylcase (mGC) as well as soluble guanylyl cyclase (sGC). Studies have found that cGMP synthesis in the olfactory is due to sGC activation by nitric oxide, a neurotransmitter. cGMP also requires increased intracellular levels of cAMP and the link between the two second messengers appears to be due to rising intracellular calcium levels.
Read more about this topic: Cyclic Guanosine Monophosphate
Famous quotes containing the word effects:
“Some of the greatest and most lasting effects of genuine oratory have gone forth from secluded lecture desks into the hearts of quiet groups of students.”
—Woodrow Wilson (1856–1924)
“Whereas Freud was for the most part concerned with the morbid effects of unconscious repression, Jung was more interested in the manifestations of unconscious expression, first in the dream and eventually in all the more orderly products of religion and art and morals.”
—Lewis Mumford (1895–1990)
“The best road to correct reasoning is by physical science; the way to trace effects to causes is through physical science; the only corrective, therefore, of superstition is physical science.”
—Frances Wright (1795–1852)