1
|
Kostin A, Alam MA, Saevskiy A, Yang C, Golshani P, Alam MN. Calcium Dynamics of the Ventrolateral Preoptic GABAergic Neurons during Spontaneous Sleep-Waking and in Response to Homeostatic Sleep Demands. Int J Mol Sci 2023; 24:8311. [PMID: 37176016 PMCID: PMC10179316 DOI: 10.3390/ijms24098311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The ventrolateral preoptic area (VLPO) contains GABAergic sleep-active neurons. However, the extent to which these neurons are involved in expressing spontaneous sleep and homeostatic sleep regulatory demands is not fully understood. We used calcium (Ca2+) imaging to characterize the activity dynamics of VLPO neurons, especially those expressing the vesicular GABA transporter (VGAT) across spontaneous sleep-waking and in response to homeostatic sleep demands. The VLPOs of wild-type and VGAT-Cre mice were transfected with GCaMP6, and the Ca2+ fluorescence of unidentified (UNID) and VGAT cells was recorded during spontaneous sleep-waking and 3 h of sleep deprivation (SD) followed by 1 h of recovery sleep. Although both VGAT and UNID neurons exhibited heterogeneous Ca2+ fluorescence across sleep-waking, the majority of VLPO neurons displayed increased activity during nonREM/REM (VGAT, 120/303; UNID, 39/106) and REM sleep (VGAT, 32/303; UNID, 19/106). Compared to the baseline waking, VLPO sleep-active neurons (n = 91) exhibited higher activity with increasing SD that remained elevated during the recovery period. These neurons also exhibited increased Ca2+ fluorescence during nonREM sleep, marked by increased slow-wave activity and REM sleep during recovery after SD. These findings support the notion that VLPO sleep-active neurons, including GABAergic neurons, are components of neuronal circuitry that mediate spontaneous sleep and homeostatic responses to sustained wakefulness.
Collapse
Affiliation(s)
- Andrey Kostin
- Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, Los Angeles, CA 91343, USA; (A.K.); (M.A.A.); (P.G.)
| | - Md. Aftab Alam
- Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, Los Angeles, CA 91343, USA; (A.K.); (M.A.A.); (P.G.)
- Department of Psychiatry, University of California, Los Angeles, CA 90095, USA
| | - Anton Saevskiy
- Scientific Research and Technology Center for Neurotechnology, Southern Federal University, 344006 Rostov-on-Don, Russia;
| | - Chenyi Yang
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697, USA;
| | - Peyman Golshani
- Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, Los Angeles, CA 91343, USA; (A.K.); (M.A.A.); (P.G.)
- Department of Psychiatry, University of California, Los Angeles, CA 90095, USA
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Md. Noor Alam
- Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, Los Angeles, CA 91343, USA; (A.K.); (M.A.A.); (P.G.)
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| |
Collapse
|
2
|
Viskaitis P, Arnold M, Garau C, Jensen LT, Fugger L, Peleg-Raibstein D, Burdakov D. Ingested non-essential amino acids recruit brain orexin cells to suppress eating in mice. Curr Biol 2022; 32:1812-1821.e4. [PMID: 35316652 DOI: 10.1016/j.cub.2022.02.067] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/10/2022] [Accepted: 02/23/2022] [Indexed: 12/22/2022]
Abstract
Ingested nutrients are proposed to control mammalian behavior by modulating the activity of hypothalamic orexin/hypocretin neurons (HONs). Previous in vitro studies showed that nutrients ubiquitous in mammalian diets, such as non-essential amino acids (AAs) and glucose, modulate HONs in distinct ways. Glucose inhibits HONs, whereas non-essential (but not essential) AAs activate HONs. The latter effect is of particular interest because its purpose is unknown. Here, we show that ingestion of a dietary-relevant mix of non-essential AAs activates HONs and shifts behavior from eating to exploration. These effects persisted despite ablation of a key neural gut → brain communication pathway, the cholecystokinin-sensitive vagal afferents. The behavioral shift induced by the ingested non-essential AAs was recapitulated by targeted HON optostimulation and abolished in mice lacking HONs. Furthermore, lick microstructure analysis indicated that intragastric non-essential AAs and HON optostimulation each reduce the size, but not the frequency, of consumption bouts, thus implicating food palatability modulation as a mechanism for the eating suppression. Collectively, these results suggest that a key purpose of HON activation by ingested, non-essential AAs is to suppress eating and re-initiate food seeking. We propose and discuss possible evolutionary advantages of this, such as optimizing the limited stomach capacity for ingestion of essential nutrients.
Collapse
Affiliation(s)
- Paulius Viskaitis
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse, Schwerzenbach 8603, Switzerland
| | - Myrtha Arnold
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse, Schwerzenbach 8603, Switzerland
| | - Celia Garau
- University of Leicester, Department of Neuroscience, Psychology & Behaviour, University Road, Leicester LE1 9HN, UK
| | - Lise T Jensen
- Aarhus University, Department of Clinical Medicine - Department of Clinical Immunology, Palle Juul-Jensens Boulevard, Aarhus 8200, Denmark
| | - Lars Fugger
- Aarhus University, Department of Clinical Medicine - Department of Clinical Immunology, Palle Juul-Jensens Boulevard, Aarhus 8200, Denmark; University of Oxford, Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, Division of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Daria Peleg-Raibstein
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse, Schwerzenbach 8603, Switzerland
| | - Denis Burdakov
- ETH Zürich, Department of Health Sciences and Technology, Schorenstrasse, Schwerzenbach 8603, Switzerland.
| |
Collapse
|