Crestani Carlos C, Tavares Rodrigo F, Alves Fernando H F, Resstel Leonardo B M, Corrêa Fernando M A
Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP 14090-090, Brazil.
Neurosci Lett. 2008 Dec 26;448(2):189-93. doi: 10.1016/j.neulet.2008.10.055. Epub 2008 Nov 1.
The diagonal band of Broca (DBB) is involved in cardiovascular control in rats. In the present study, we report the effect of acute and reversible neurotransmission inhibition in the DBB by bilateral microinjection of the nonselective neurotransmission blocker CoCl(2) (1mM, 100 nL) on the cardiac baroreflex response in unanesthetized rats. Local DBB neurotransmission inhibition did not affect baseline values of either blood pressure or heart rate, suggesting no tonic DBB influence on cardiovascular system activity. However, CoCl(2) microinjections enhanced both the reflex bradycardia associated with blood pressure increases caused by i.v. infusion of phenylephrine and tachycardiac response evoked by blood pressure decreases caused by i.v. infusion of sodium nitroprusside. An increase in baroreflex gain was also observed. Baroreflex returned to control values 60 min after CoCl(2) microinjections, confirming its reversible effect. In conclusion, our data suggest that synapses within DBB have a tonic inhibitory influence on both the cardiac parasympathetic and sympathetic components of the baroreflex.
布罗卡斜角带（DBB）参与大鼠的心血管控制。在本研究中，我们报告了通过双侧微量注射非选择性神经传递阻滞剂氯化钴（CoCl₂，1 mM，100 nL）对未麻醉大鼠的DBB进行急性和可逆性神经传递抑制，对其心脏压力反射反应的影响。局部DBB神经传递抑制并未影响血压或心率的基线值，这表明DBB对心血管系统活动没有紧张性影响。然而，氯化钴微量注射增强了静脉注射去氧肾上腺素引起的血压升高相关的反射性心动过缓，以及静脉注射硝普钠引起的血压降低所诱发的心动过速反应。还观察到压力反射增益增加。在氯化钴微量注射60分钟后，压力反射恢复到对照值，证实了其可逆作用。总之，我们的数据表明，DBB内的突触对压力反射的心脏副交感神经和交感神经成分均有紧张性抑制作用。
