Abstract
The cation channel subunit TRPC1 is strongly expressed in central neurons including neurons in the CA1 region of the hippocampus where it forms complexes with TRPC4 and TRPC5. To investigate the functional role of TRPC1 in these neurons and in channel function, we compared current responses to group I metabotropic glutamate receptor (mGluR I) activation and looked for major differences in dendritic morphology in neurons from TRPC1+/+ and TRPC1−/− mice. mGluR I stimulation resulted in the activation of a voltage-dependent nonselective cation current in both genotypes. Deletion of TRPC1 resulted in a modification of the shape of the current-voltage relationship, leading to an inward current increase. In current clamp recordings, the percentage of neurons that responded to depolarization in the presence of an mGluR I agonist with a plateau potential was increased in TRPC1−/− mice. There was also a small increase in the minor population of CA1 neurons that have more than one apical dendrite in TRPC1−/− mice. We conclude that TRPC1 has an inhibitory effect on receptor-operated nonselective cation channels in hippocampal CA1 neurons probably as a result of heterotetramer formation with other TRPC isoforms, and that TRPC1 deletion has only minor effects on dendritic morphology.
Highlights
Many neuron types respond to the activation of phospholipase C (PLC)-coupled metabotropic neurotransmitter or growth factor receptors with the activation of cation currents
We show that metabotropic glutamate receptors type I (mGluR I)-activated, voltage-dependent, nonselective cation currents are increased in neurons from TRPC1−/− mice and that neuron morphology displays only modest but significant changes following deletion of TRPC1
Group I mGluR-Activated cation Currents are Increased in Hippocampal CA1 Neurons from TRPC1−/− Mice
Summary
Many neuron types respond to the activation of phospholipase C (PLC)-coupled metabotropic neurotransmitter or growth factor receptors with the activation of cation currents. Molecular candidates for some of the channels involved in these responses are members of the canonical/classical TRPC subfamily of cation channels [1,2]. The seven TRPC isoforms (TRPC1–TRPC7) can be subdivided on the basis of sequence similarity and some functional properties into four groups (1: TRPC1, 2: TRPC2, 3: TRPC3/6/7 and 4: TRPC4/5) [3,4]. TRPC2 is mainly found in the vomeronasal organ, whereas the other TRPC channels are more widely expressed, with more than one isoform often being detected in the same region [4]. Since most cell types contain multiple TRPC isoforms, the formation of heterotetrameric channels with different properties is possible. All TRPC isoforms coassemble to form homomultimers, but TRPC1 is
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
