Vesicular glutamate (VGlut), GABA (VGAT), and acetylcholine (VACht) transporters in basal forebrain axon terminals innervating the lateral hypothalamus.
The basal forebrain (BF) is known to play important roles in cortical activation and sleep, which are likely mediated by chemically differentiated cell groups including cholinergic, gamma-aminobutyric acid (GABA)ergic and other unidentified neurons. One important target of these cells is the lateral hypothalamus (LH), which is critical for arousal and the maintenance of wakefulness. To determine whether chemically specific BF neurons provide an innervation to the LH, we employed anterograde transport of 10,000 MW biotinylated dextran amine (BDA) together with immunohistochemical staining of the vesicular transporter proteins (VTPs) for glutamate (VGluT1, -2, and -3), GABA (VGAT), or acetylcholine (ACh, VAChT). In addition, we applied triple staining for the postsynaptic proteins (PSPs), PSD-95 with VGluT or Gephyrin (Geph) with VGAT, to examine whether the BDA-labeled varicosities may form excitatory or inhibitory synapses in the LH. Axons originating from BDA-labeled neurons in the magnocellular preoptic nucleus (MCPO) and substantia innominata (SI) descended within the medial forebrain bundle and extended collateral varicose fibers to contact LH neurons. In the LH, the BDA-labeled varicosities were immunopositive (+) for VAChT ( approximately 10%), VGluT2 ( approximately 25%), or VGAT ( approximately 50%), revealing an important influence of newly identified glutamatergic together with GABAergic BF inputs. Moreover, in confocal microscopy, VGluT2+ and VGAT+ terminals were apposed to PSD-95+ and Geph+ profiles respectively, indicating that they formed synaptic contacts with LH neurons. The important inputs from glutamatergic and GABAergic BF cells could thus regulate LH neurons in an opposing manner to stimulate vs. suppress cortical activation and behavioral arousal reciprocally.
Henny
Pablo
P
Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada.
Jones
Barbara E
BE
D000818:Animals; D001143:Arousal / Q000502:physiology; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003911:Dextrans / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D007026:Hypothalamic Area, Lateral / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000378:metabolism*; D011301:Preoptic Area / Q000166:cytology / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism*; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D013194:Staining and Labeling / Q000379:methods; D013377:Substantia Innominata / Q000166:cytology / Q000378:metabolism*; D050494:Vesicular Acetylcholine Transport Proteins / Q000378:metabolism; D050496:Vesicular Glutamate Transport Proteins / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism; D050481:Vesicular Neurotransmitter Transport Proteins / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D002352:Carrier Proteins; D003911:Dextrans; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D050494:Vesicular Acetylcholine Transport Proteins; D050496:Vesicular Glutamate Transport Proteins; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; D050481:Vesicular Neurotransmitter Transport Proteins; C076397:biotinylated dextran amine; C073441:gephyrin; D005680:gamma-Aminobutyric Acid; D001710:Biotin