Role of peripheral vestibular receptors in the control of blood pressure following hypotension

Hypotension is one of the potential causes of dizziness. In this review, we summarize the studies published in recent years about the electrophysiological and pharmacological mechanisms of hypotension-induced dizziness and the role of the vestibular system in the control of blood pressure in response to hypotension. It is postulated that ischemic excitation of the peripheral vestibular hair cells as a result of a reduction in blood flow to the inner ear following hypotension leads to excitation of the central vestibular nuclei, which in turn may produce dizziness after hypotension. In addition, excitation of the vestibular nuclei following hypotension elicits the vestibulosympathetic reflex, and the reflex then regulates blood pressure by a dual-control (neurogenic and humoral control) mechanism. In fact, recent studies have shown that peripheral vestibular receptors play a role in the control of blood pressure through neural reflex pathways. This review illustrates the dual-control mechanism of peripheral vestibular receptors in the regulation of blood pressure following hypotension.

Long-term results of personalized treatment in 72 breast cancer patients who failed chemotherapy / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy and prognostic factors of personalized treatment for breast cancer patients who failed chemotherapy.</p><p><b>METHODS</b>Seventy-two patients with breast cancer who failed chemotherapy were treated at the Tumor Hospital of Harbin Medical University from January 2001 to January 2012. Among them, 42 cases received 5.6 cycles (range, 4-8 cycles) of postoperative adjuvant chemotherapy, and 30 cases received 12.2 cycles (range, 6-22 cycles), both postoperative adjuvant and salvage chemotherapy. All of the 72 patients of stage IV were given personalized treatment. Under guidance of the principle that multidisciplinary treatment improves control rate but does not or less damage the normal tissues and host immune function, precise radiotherapy combined with Chinese herbal medicine (CHM), biological agent and others were chosen for the patients.</p><p><b>RESULTS</b>The median survival time was 20 months. Univariate analysis showed that non-invasive ductal carcinoma, less metastasized organs, without brain, liver and lung metastasis, Karnofsky performance scores ≥ 80, not combined with chemotherapy, and multiple courses of Chinese herbal medicine and biolojical agent treatment had significant impact on survival (P < 0.05). Multivariate analysis showed that no brain metastasis, non-invasive ductal carcinoma, and Chinese herbal medicine and biological agent treatment ≥ 7 courses and not combined with chemotherapy had obvious significance (P < 0.05). The rate of grade 3 and 4 treatment-related hematological toxicity was 8.3% (6/72) and 5.6% (4/72), respectively. All the patients with grade 4 hematological toxicity were the cases of grade 3 at hospital admission. No grade 3 and 4 acute radiation damages of the lung and liver were noticed.</p><p><b>CONCLUSION</b>Chinese herbal medicine combined with biological agents and others prolongs survival time in breast cancer patients who failed chemotherapy, and provides an alternative treatment modality for them.</p>

Changes of gamma-aminobutyric acid and glycine released in the medial vestibular nucleus following acute hypotension in conscious rats / 生理学报

To understand whether some amino acids in the medial vestibular nucleus (MVN) of conscious rats are involved in the regulation of blood pressure, microdialysis technique and high performance liquid chromatography (HPLC) were used to measure the changes of gamma-aminobutyric acid (GABA) and glycine (Gly) in this central area. Wistar rats (250-350 g) were randomly divided into three experimental groups: the control group with intact labyrinths; the ipsilateral MVN of unilateral labyrinthectomy (UL); contralateral MVN of the UL. Acute hypotension was induced by intravenous infusion of sodium nitroprusside (SNP). Unilateral chemical labyrinthectomy was performed 14 days before the start of the experiment to eliminate afferent signals from the peripheral vestibular receptors in the inner ear. Blood pressure decreased by 30% after SNP injection. In the control group, GABA and Gly release reduced to 43.53%+/-6.58% (P<0.01) and 62.24%+/-7.51% (P<0.01) respectively in the MVN following SNP-induced acute hypotension in conscious rats. In the contralateral MVN of UL, GABA and Gly release also reduced to 45.85%+/-17.27% (P<0.01) and 73.30%+/-3.00% (P<0.01) respectively following SNP-induced acute hypotension in conscious rats. In contrast, in the ipsilateral MVN of UL, GABA and Gly releases were not changed following SNP-induced acute hypotension in conscious rats. These results suggest that the SNP-induced acute hypotension may influence the activity of the neurons in the MVN by the afferent impulses from the peripheral vestibular organ, and that GABA and Gly may be involved in this process.

Effects of purinergic analogues on spontaneous contraction and electrical activities of gastric antral circular muscle in guinea-pig / 生理学报

In order to investigate the role of non-adrenergic non-cholinergic nerves in regulating mechanical and electrical activity of gastric circular smooth muscle, the effects of ATP and its analogues on gastric motility and electrical activities were observed in guinea-pig. In organ bath system, isometric force of the circular smooth muscle of guinea-pig gastric antrum was measured. Electrical activity of the muscle was recorded by using intracellular microelectrode. Electrical and mechanical activities were recorded by chart recorder. ATP and 2-MeSATP potentiated the mechanical activity but did not affect electrical activity in gastric circular smooth muscle. ATP and 2-MeSATP-induced contraction was effectively blocked by nonselective P2y-purinoceptor antagonist, reactive-blue-2 and suramin, but ATP-induced contraction was not blocked by alpha,beta-MeATP-induced desensitization of P2x-purinoceptors. However, alpha,beta-MeATP, P2x-purinoceptor agonist, attenuated slow waves with membrane hyperpolarization and inhibited contraction. The relaxation by beta,gamma-MeATP was blocked by alpha,beta-MeATP-induced desensitization of P2x-purinoceptors. ATP-induced contraction was blocked by external calcium-free, but not by nicardipine, a L-type calcium channel blocker. Indomethacin, a nonselective cyclooxygenase inhibitor, did not block ATP-induced contraction. The results suggest that: (1) ATP- and analogues-induced contraction is mediated by P2y-purinoceptor, whereas alpha,beta-MeATP-induced relaxation by P2x-purinoceptor in guinea-pig gastric antral circular smooth muscle. (2) ATP-induced contraction is dependent on extracellular calcium, but Ca2+ entry is not mediated by L-type calcium channel. (3) Prostaglandins are not involved in ATP- and analogue-induced contraction of gastric circular smooth muscle in guinea-pigs, and alpha,beta-MeATP-induced relaxation is related to membrane hyperpolarization.