Metabotropic receptor



Metabotropic receptor is a subtype of membrane receptors at the surface or in vesicles of eukaryotic cells.

In the nervous system, based on their structural and functional characteristics, signal transduction mechanisms.

What both receptor types have in common is that they are activated by specific neurotransmitters. When an ionotropic receptor is activated, it opens a channel that allows ions such as Na+, K+, or Cl- to flow. In contrast, when a metabotropic receptor is activated, a series of intracellular events are triggered that also results in ion channel opening but must involve a range of second messenger chemicals.

Examples

This class of receptors includes the neuropeptides (Austin, 2004; Purves et al., 2001) and endocannabinoids.

Structure

All metabotropic receptors are monomeric proteins with seven transmembrane domains. The protein's N terminus is on the extracellular side of the membrane and its C terminus is on the intracellular side (Purves et al., 2001).

Function

Metabotropic receptors have neurotransmitters as molecules in turn, channels associated with these receptors take longer to open than ionotropic receptors do, and they are thus not involved in mechanisms that require quick responses (Kandel et al., 2000, p. 240). However, metabotropic receptors also remain open from seconds to minutes (Kandel et al., 2000, p. 250-251). Thus they have a much longer-lasting effect than ionotropic receptors, which open quickly but only remain open for a few milliseconds (Austin, 2004). While ionotropic channels have an effect only in the immediate region of the receptor, the effects of metabotropic receptors can be more widespread through the cell.

Metabotropic receptors can both open and close channels. They can make a membrane more excitable by closing G-protein-coupled receptors, or GPCRs (Kandel et al., 2000, p. 229).

References

  • Austin V. 2004. Fundamentals of the nervous system and nervous tissue. Pearson Education, Inc., Benjamin Cummings. From, Marieb E.N. 2004. Human Anatomy & Physiology, Sixth Edition. [1]
  • Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science, 4th ed., pp.178-180. McGraw-Hill, New York (2000). ISBN 0-8385-7701-6
  • Purves D., Augustine G.J., Fitzpatrick D., Katz L.C., LaMantia A.S., McNamara J.O., and Williams S.M. 2001. Neuroscience, Second Edition. Sinauer Associates, Inc. [2]
  • Schmitz D, Mellor J, Nicoll RA. Presynaptic kainate receptor mediation of frequency facilitation at hippocampal mossy fiber synapses. Science. 2001 Mar 9;291(5510):1972-6. PMID 11239159
  • Zimmerberg, B. 2002. Dopamine receptors: A representative family of metabotropic receptors. Multimedia Neuroscience Education Project. [3]

External links

  • IUPHAR Receptor Database
 
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