Loss of orexinA-immunoreactive neurons in the LH after orexin-SAP treatment.

<p>A and B are low and high magnification photomicrographs of orexin-ir neurons in coronal sections of the brain in the blank-SAP-treated rat. C and D as A and B, but from the orexin-SAP-treated rat. Orexin neurons were significantly fewer after damage of the LH by orexin-SAP-treatment with a few residual ones indicated by black arrows. 3V: third ventricle, LH: lateral hypothalamus, F: Fornix.</p

ASICs antagonist blocking acidification-induced increase of PND.

<p>A: Histological staining with neutral red: the sky blue spot was the injection site in the LH. Scale bar, 1 mm. B: Plot of the injection sites projected on Bregma −2.6 mm section: the solid dots were inside and the hollow ones outside of the LH. Scale bar, 1 mm. C: Unilateral microinjection of 0.1 µl ACSF (pH 6.5) into the LH increased raw PND (top) and iPND (bottom). Pre-treatment of amiloride (10 mM) or PcTX1 (10 nM) blocked the effect. Microinjection of ACSF (pH 7.4) served as the control. D: Group data show the effects of amiloride and PcTX1 on acidification-induced iPND (n = 6, *** P<0.001 relative to control, ^### P<0.001 relative to pH 6.5). E: Time course of iPND response to acidification of the LH. Please note that the response peaked at 20 min (n = 6, *** P<0.001 relative to pH 7.4). F: Responses of respiratory drive (PA/Ti). Note that amiloride and PcTX1 inhibited the acidification-induced effect (n = 6, ^# P<0.05 relative to pH 7.4, ** P<0.01 relative to pH 6.5). G: Inspiratory time (Ti) was increased by acidification but not statistically significant (<i>v.s.</i> pH 7.4).</p

Co-expression of ASIC1 and OrexinA in the LH of adult SD rats.

<p>A representative confocal photomicrograph showing co-staining of orexinA and ASIC1 on neurons in the LH of an adult SD rat. <b>A:</b> OrexinA-ir neurons (green, FITC). <b>B:</b> ASIC1-ir neurons (red, cy3). <b>C:</b> Overlay of A and B.</p

Changes in SBP and protein expressions of ACE and AT₁R in the RVLM of stressed rats.

<p><i>*P<</i>0.05, <i>**P<</i>0.01, compared with the control group (0 day).</p

Effect of microinjection of ACSF with different pH and ASICs inhibitor into LH on RR, MAP and HR.

<p>Effect of microinjection of ACSF with different pH and ASICs inhibitor into LH on RR, MAP and HR.</p

Schematic diagram showing the relationship between the renin-angiotensin system and stress-induced hypertension.

<p>ACE upregulation and/or ACE2 downregulation result in Ang II↑ and/or Ang-(1–7)↓. Ang, Angiotensin; ACE, angiotensin-converting enzyme; ACE2, angiotensin-converting enzyme homolog; AT₁R, Ang II type 1 receptor; AT₂R, Ang II type 2 receptor; SIH, stress-induced hypertension</p

Chromatographic plots of amino acids in the RVLM following microinjection.

<p>ACSF in normal rats (A), Ang II in normal rat (B) or Ang II in SIH rat (C). The abscissa is retention time (min). The ordinate is absorbance. Asp, aspartate; Glu, Glutamate; Asn, asparagine; Gln, Glutamine; Gly, Glycine; Tau, taurine; GABA, γ-aminobutyric acid.</p

Effects of microinjection of losartan, PD123319 and Ang779 into the RVLM onΔMAP.

<p><i>*P<</i>0.05, compared with the normotensive control group (n = 8 in each group).</p

Effects of microinjection of Ang II and Ang-(1–7) into the RVLM on HR.

*<p><i>P</i><0.05 compared with the artificial cerebrospinal fluid (ACSF) group; ^#<i>P</i><0.05 compared with the normotensive animal (n = 8 in each group).</p

Effects of microinjection of Ang-(1–7) or Ang779 into the RVLM on local release of amino acids.

*<p><i>P</i><0.05 compared with the ACSF group at the same time point; ^Δ<i>P</i><0.05 compared with baseline (10 min prior to microinjection); ^#<i>P</i><0.05 compared with the normotensive rats at the same time point. Amino acids (AA) were measured at baseline, 1^st, 2^nd, 3^rd 10 min after administration of ACSF, Ang-(1–7) or Ang779, respectively (n = 8 in each group). Asp, aspartate; Glu, Glutamate; Gly, Glycine; Tau, taurine; GABA, γ-aminobutyric acid.</p