Leptin increases sympathetic nerve activity via induction of its own receptor in the paraventricular nucleus
- Department of Physiology and Pharmacology, United States
- Department of Anesthesiology and Perioperative Medicine, United States
- Department of Neurological Surgery, United States
- Department of Pediatrics, Pape Family Pediatric Research Institute, Brenden-Colson Center for Pancreatic Care Oregon Health & Science University, United States
Figures
Figure 1
Effects of PVN leptin on LSNA, HR, and MAP.
(A) Representative experiments showing that bilateral nanoinjections (beginning at arrow) of leptin, but not aCSF, into the PVN increased LSNA. (B-D) Bilateral nanoinjections of leptin, but not …
Figure 2
Effects of PVN leptin on baroreflex control of LSNA and HR.
(A-B) Representative experiments showing effects of PVN leptin (60 ng) on baroreflex control of LSNA (A) and HR (B). (C) Grouped LSNA data. PVN nanoinjection of leptin enhanced baroreflex control of …
Figure 3
Effects of DMH and ArcN leptin on LSNA, HR, and MAP, and baroreflex control of LSNA and HR.
(A) Bilateral DMH nanoinjections of leptin (n = 4) enhanced basal LSNA and baroreflex control of LSNA (increased baroreflex gain, maximum, minimum); however, while HR gain was enhanced, basal HR and …
Figure 4
Effects of PVN leptin on BAT SNA in warm and cooled rats.
(A) In rats with warm skin temperature (37.2 ± 0.2°C), PVN leptin (n = 7) increased BAT SNA, without significantly altering BAT temperature. PVN aCSF (n = 4) did not alter these variables. (B) Top, …
Figure 5
PVN leptin increases LSNA in estrogen (E2)-treated ovariectomized (OVX) female rats (n = 3), but not OVX rats (n = 3).
*: p<0.05, compared to baseline control values.
Figure 6
Leptin receptors (LepR) are expressed throughout the PVN in male rats, but at much lower levels than in the ArcN.
Images from a representative rat showing the presence and distribution of LepR in male rats (red puncta) throughout the PVN and ArcN. Individual plates illustrate the changes in LepR distribution …
Figure 7
Leptin receptors (LepR) are expressed throughout the PVN in male mice, but at much lower levels than in the ArcN.
Images are from one representative mouse (from n = 5). PVN and ArcN levels (mm from bregma) are displayed in the lower left corner of each micrograph. Magnified sections are also included as insets …
Figure 8
PVN leptin induces the expression of the LepR.
(A) Representative histological image showing PVN injection sites. (B) Top. Representative experiment showing that a unilateral injection of leptin slowly increases LSNA. Bottom. Grouped data (n = 6)…
Figure 9
Blockade of ionotropic glutamate receptors with kynurenate (KYN), but not of MC4R with SHU9119, partially reverses the sympathexcitatory effects of PVN leptin.
Left: bilateral PVN KYN injections; Right: bilateral PVN SHU9119 injections. (A) Representative experiment showing that PVN nanoinjections of leptin significantly increased LSNA after 90 min. …
Figure 10
PVN LepR are rarely expressed in PVN microglia in untreated (naïve) male rats.
Top. Representative images (from n = 2) showing Iba-1 (green, ihc) and LepR (red puncta, FISH) in PVN (A) and ArcN (B); higher magnifications of boxed subsections show rare overlap of iba-1 and LepR …
Figure 11
PVN LepR are rarely expressed in PVN microglia in rats treated with Leptin/aCSF.
Top. Representative images (from n = 3) showing PVN Iba-1 (green, ihc) and LepR (red puncta, FISH) in leptin-treated (A) and aCSF-treated (B) rats; right images are magnifications showing rare …
Figure 12
PVN LepR are not expressed in astroglia in naïve or PVN leptin/aCSF treated rats.
Representative images showing GFAP (green, ihc) and LepR (red, FISH) from naïve (A-D, n = 6) or treated (E-H, n = 4) rats. In untreated rats, images from the PVN (A and C) and the ArcN (B and D), …
Figure 13
PVN leptin does not reduce the sympathoexcitatory response to PVN DHK.
Top, representative experiments; Bottom, grouped data. (A) In untreated rats, bilateral PVN DHK increased LSNA (55 ± 9%) and MAP (p<0.05; n = 6). (B) Two hours after bilateral nanoninjections of …
Figure 14
LepR are expressed in glutamatergic neurons, some of which project to the rostral ventrolateral medulla (RVLM; contain CTB).
Top. Representative sections from an untreated rat (A) and leptin-treated rat (B) showing that LepR (Red punta, FISH) are expressed in glutamateric neurons (white; FISH), some of which contain the …
Figure 15
Leptin activates PVN glutamatergic neurons.
(A) Left. Representative experimental tracing showing that PVN glutamatergic neuronal activity (GCaMP-6 fluorescence) both increases and decreases following treatment of a PVN slice with …
Figure 16
LepR are commonly, but not exclusively, found in TRH neurons.
Representative images (n = 3) from several levels of the PVN (−0.84 to −2.28 from bregma) showing the expression of LepR (red puncta) in TRH neurons (green). Blue is DAPI nuclear stain. Right panel …
Figure 17
LepR are expressed in TRH neurons that project to the RVLM.
Representative image from one rat that received RVLM CTB showing that many CTB-containing PVN neurons (white) express TRH (green) and the LepR (red puncta), although CTB-containing but TRH negative, …
Figure 18
TRH increases LSNA and BAT SNA.
Nanoinjections of TRH into the RVLM (A and B; n = 5) increase LSNA, HR, and MAP, whereas RVLM injections of aCSF (B; n = 3) have no effects. Nanoinjections of TRH into the DMH increase LSNA, HR, and …
Figure 19
Models that summarize the results and hypothesize potential roles during fasting or obesity.
(A) Summary of findings. (B and C) Models illustrating hypothesized role of PVN LepR in the regulation of the HPT axis and LSNA and BATSNA with fasting and obesity.
See text for details.
Figure 20
Histological maps (adapted from Paxinos and Watson, 2007) illustrating nanoinjection sites.
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Genetic reagent (M. musculus) | VGlut2-cre; C57BL/6J Slc17a6tm2(cre)Lowl | Jackson Laboratory; reference (Vong et al., 2011) | Stock #: 016963 RRID:IMSR_JAX:016963 | |
| Antibody | Monoclonal mouse anti-GFAP | Sigma | Catalog#: G3893 RRID:AB_477010 | Ihc (1:500) |
| Antibody | Goat anti-mouse 488 | Jackson ImmunoResearch | Catalog #: 115-545-166 RRID:AB_2338852 | Ihc (1:1500) |
| Antibody | Rabbit anti-iba1 | Wako | Catalog #: 019–19741 RRID:AB_839504 | Ihc (1:250) |
| Antibody | Goat Anti-Cholera Toxin B Subunit | List Biological Laboratories, Inc | Catalog #: 703 | Ihc (1:250) |
| Antibody | Donkey Anti-Rabbit IgG (H+L) | Jackson ImmunoResearch | Catalog #: 711-545-152 RRID:AB_2313584 | Ihc (1:1000) |
| Antibody | Donkey anti goat 488 | Jackson ImmunoResearch | Catalog #: #705-545-147 RRID:AB_2336933 | Ihc (1:1000) |
| Recombinant DNA reagent | pAAV.Syn.Flex.GCaMP6s.WPRE.SV40 | Douglas Kim and GENIE project | RRID:Addgene_100845 | |
| Commercial assay or kit | RNAScope Fluorescent Multiplex Kit | ACDBio | Catalog #: 320850 |
Table 1
RNAScope probes (ACDBio).
| Target | Species | Catalog # |
|---|---|---|
| LepR | Rat (Norway) | 415951-C2 |
| Vglut2 | Rat (Norway) | 317011-C2 |
| Iba1 | Rat (Norway) | 457731-C3 |
| TRH | Rat (Norway) | 406621-C1 |
| Positive Control (Polr2a (C1) and PPIB (C2), UBC (C3) | Rat (Norway) | 320891 |
| Negative Control (DapB (of Bacillus subtilis strain) | Rat/mouse | 320871 |
| Positive Control | Mouse | 320881 |
| LepR | Mouse | 402731-C2 |
