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- Title
Simulated GABA Synaptic Input and L-Type Calcium Channels Form Functional Microdomains in Hypothalamic Gonadotropin-Releasing Hormone Neurons.
- Authors
Hemond, Peter J.; O'Boyle, Michael P.; Roberts, Carson B.; Delgado-Reyes, Alfonso; Hemond, Zoe; Suter, Kelly J.
- Abstract
Hypothalamic gonadotropin-releasing hormone (GnRH) neurons integrate the multiple internal and external cues that regulate sexual reproduction. In contrast to other neurons that exhibit extensive dendritic arbors, GnRH neurons usually have a single dendrite with relatively little branching. This largely precludes the integration strategy in which a single dendritic branch serves as a unit of integration. In the present study, we identify a gradient in L-type calcium channels in dendrites of mouse GnRH neurons and its interaction with GABAergic and glutamatergic inputs. Higher levels of L-type calcium channels are in somata/proximal dendrites (i.e., 0 -26 µm) and distal dendrites (∼130 µm dendrite length), but intervening midlengths of dendrite (∼27-130 µm) have reduced L-type calcium channels. Using uncaging of GABA, there is a decreasing GABAergic influence along the dendrite and the impact of GABAA receptors is dependent on activation of L-type calcium channels. This results in amplification of proximal GABAergic signals and attenuation of distal dendritic signals. Most interestingly, the intervening dendritic regions create a filter through which only relatively high-amplitude, low-frequency GABAergic signaling to dendrites elicits action potentials. The findings of the present study suggest that GnRH dendrites adopt an integration strategy whereby segments of single nonbranching GnRH dendrites create functional microdomains and thus serve as units of integration.
- Subjects
GONADOTROPIN releasing hormone; CALCIUM channels; NEURONS; DENDRITES; ACTION potentials; ION channels; LABORATORY mice
- Publication
Journal of Neuroscience, 2012, Vol 32, Issue 26, p8756
- ISSN
0270-6474
- Publication type
Article
- DOI
10.1523/JNEUROSCI.4188-11.2012