Arnolda L, Minson J, Kapoor V, Pilowsky P, Llewellyn-Smith I, Chalmers J
Department of Medicine, Flinders Medical Centre, Adelaide, South Australia.
Kidney Int Suppl. 1992 Jun;37:S2-7.
There is compelling evidence for the participation of excitatory and inhibitory amino acids in the neural regulation of blood pressure in the normotensive rat. This is most clearly evident in the neural pathways which form the baroreceptor reflex arc. Excitatory amino acids are contained in baroreceptor afferents, neurons in the nucleus tractus solitarius (NTS) and neurons in the rostral ventrolateral medulla (RVLM). Inhibitory neurons in the caudal ventrolateral medulla (CVLM) contain gamma-aminobutyric acid. Electrophysiological and pharmacological evidence indicates that amino acid neurotransmitters are critically important to the normal function of these integrative sites in the baroreceptor reflex. Spontaneously hypertensive rats (SHR) differ from Wistar Kyoto (WKY) controls in their responses to stimulation, inhibition or lesions of neurons in the baroreceptor arc. One week after baroreceptor denervation, blood pressure is elevated in WKY but not in SHR. Stimulation of the CVLM results in a greater fall in pressure in SHR than WKY, whereas injection of tetrodotoxin into the CVLM results in a smaller increase in pressure in SHR. Blockade of glutamate receptors in the spinal cord attenuates the response to stimulation of the RVLM in both SHR and WKY, but reduces resting blood pressure in SHR only. These experiments suggest that altered activity in amino acid pathways contributes to the pathogenesis of hypertension in SHR.
有令人信服的证据表明，兴奋性和抑制性氨基酸参与正常血压大鼠的血压神经调节。这在构成压力感受器反射弧的神经通路中最为明显。压力感受器传入神经、孤束核（NTS）中的神经元和延髓头端腹外侧（RVLM）中的神经元都含有兴奋性氨基酸。延髓尾端腹外侧（CVLM）中的抑制性神经元含有γ-氨基丁酸。电生理和药理学证据表明，氨基酸神经递质对压力感受器反射中这些整合部位的正常功能至关重要。自发性高血压大鼠（SHR）与Wistar Kyoto（WKY）对照在对压力感受器弧中神经元的刺激、抑制或损伤的反应方面存在差异。压力感受器去神经支配一周后，WKY的血压升高，而SHR则不然。刺激CVLM导致SHR的血压下降幅度大于WKY，而向CVLM注射河豚毒素导致SHR的血压升高幅度较小。阻断脊髓中的谷氨酸受体可减弱SHR和WKY对刺激RVLM的反应，但仅降低SHR的静息血压。这些实验表明，氨基酸通路的活性改变有助于SHR高血压的发病机制。
