The lateral hypothalamus (LH) is implicated in the physiological and behavioral responses during stressful events. However, the local neurochemical mechanisms related to control of stress responses by this hypothalamic area are not completely understood. Therefore, in this study we evaluated the involvement of CRFergic neurotransmission acting through the CRF₁ receptor within the LH in cardiovascular responses evoked by an acute session of restraint stress in rats. For this, we investigated the effect of bilateral microinjection of different doses (0.01, 0.1 and 1 nmol/100 nL) of the selective CRF₁ receptor antagonist CP376395 into the LH on arterial pressure and heart rate increases and decrease in tail skin temperature evoked by acute restraint stress. We found that all doses of the CRF₁ receptor antagonist microinjected into the LH decreased the restraint-evoked tachycardia, but without affecting the arterial pressure and tail skin temperature responses. Additionally, treatment of the LH with CP376395 at the doses of 0.1 and 1 nmol/100 nL increased the basal values of both heart rate and arterial pressure, whereas the dose of 0.1 nmol/100 nL decreased the skin temperature. Taken together, these findings indicate that CRFergic neurotransmission in the LH, acting through activation of local CRF₁ receptors, plays a facilitatory role in the tachycardia observed during aversive threats, but without affecting the pressor and tail skin temperature responses. Our results also provide evidence that LH CRFergic neurotransmission in involved in tonic maintenance of cardiovascular function.

外侧下丘脑 (LH) 与压力事件期间的生理和行为反应有关。然而，与该下丘脑区域控制应激反应相关的局部神经化学机制尚不完全清楚。因此，在这项研究中，我们评估了 CRFergic 神经传递通过LH 内的CRF ₁受体起作用，参与由大鼠急性束缚应激引起的心血管反应。为此，我们研究了双侧显微注射不同剂量（0.01、0.1 和 1 nmol/100 nL）的选择性 CRF ₁受体拮抗剂 CP376395 进入 LH 对急性束缚应激引起的动脉压和心率增加和尾部皮肤温度降低。我们发现，所有剂量的 CRF ₁受体拮抗剂显微注射到 LH 中都减少了束缚诱发的心动过速，但不影响动脉压和尾部皮肤温度反应。此外，用 0.1 和 1 nmol/100 nL 剂量的 CP376395 治疗 LH 增加了心率和动脉压的基础值，而 0.1 nmol/100 nL 剂量降低了皮肤温度。总之，这些发现表明 LH 中的 CRF 能神经传递，通过激活局部 CRF ₁受体，在厌恶威胁期间观察到的心动过速中起促进作用，但不影响升压和尾部皮肤温度反应。我们的结果还提供证据表明 LH CRFergic 神经传递参与心血管功能的强直维持。