The combination of fentanyl and diazepam significantly decreases systemic vascular resistance and blood pressure. We attempted to elucidate the reason the combination of these drugs can reduce blood pressure. In alpha-chloralose-anesthetized dogs, we investigated the effects of fentanyl and diazepam on mean arterial pressure (MAP) and arterial baroreflex control of renal sympathetic nerve activity (RSNA) in both intact (Study 1) and baroreflex-denervated dogs (Study 2). Study 1 included five dogs that received fentanyl 10 micrograms/kg followed by diazepam 0.4 mg/kg after a 10-min interval. Five more received both drugs in reversed sequence. The arterial baroreflex depressor test was performed with sodium nitroprusside before and after administration of each drug. Sensitivity of arterial baroreflex was examined by using the ratio of maximum increase of RSNA to maximum decrease of MAP (delta RSNA/delta MAP). RSNA and MAP significantly decreased only after both drugs had been administered (P < 0.05). Fentanyl alone did not attenuate arterial baroreflex sensitivity. Diazepam after fentanyl and diazepam alone attenuated baroreflex sensitivity to the same extent (P < 0.05). Study 2 comprised 14 dogs that underwent further surgical preparation of bilateral carotid sinus, aortic, and vagal nerve denervations. Seven received fentanyl, 5 and 10 micrograms/kg, and the other seven received diazepam, a total of 0.4 mg/kg. Fentanyl decreased both RSNA and MAP. Diazepam decreased only MAP significantly. The results indicate that fentanyl decreases mainly sympathetic outflow, whereas diazepam attenuates arterial baroreflex. We conclude that these combined effects of fentanyl and diazepam significantly decrease arterial blood pressure.
One reason for the reported conflicting results of the effect of ketamine on hemodynamics and respiration may be variations in afferent inputs from peripheral receptors to the central nervous system. In order to evaluate unmasked direct effects of ketamine on sympathetic nerve and phrenic nerve outflow, totally deafferented (involving vagus, sinus nerve, aortic depressor nerve) rabbits (n = 18), rabbits with vagotomy (n = 21), and neuraxis-intact rabbits (n = 6) were used in this study. The animals were anesthetized with urethane and mechanically ventilated. Ketamine 0.5, 1, or 2 mg/kg was injected intravenously and mean arterial pressure (MAP), heart rate (HR), and integrated renal sympathetic nerve and phrenic nerve activity (IRSNA, IPNA) were recorded before, and 1, 2, 3, 5, and 10 min after injection. MAP and IRSNA were significantly decreased, even by the smallest dose of ketamine, in the totally deafferented group. IPNA was decreased by the largest dose of ketamine only in the totally deafferented group. On the other hand, spontaneous respiratory frequency was decreased in the totally deafferented and vagotomy groups, but more so in the totally deafferented group. In the neuraxis-intact group, the only significant change with the largest dose of ketamine, 2 mg/kg was a slight increase in HR. We conclude that ketamine can suppress vasomotor and respiratory centers directly, and that the suppression is counterbalanced by afferent inputs from peripheral receptors.
Bronchomotor tone is regulated by contraction and relaxation of airway smooth muscle (ASM). A weakened ASM relaxation might be a cause of the airway hyperresponsiveness, a characteristic feature of bronchial asthma. Pituitary adenylyl cyclase-activating polypeptide (PACAP) is known as a mediator that causes ASM relaxation. To date, whether or not the PACAP responsiveness is changed in asthmatic ASM is unknown. The current study examined the hypothesis that relaxation induced by PACAP is reduced in bronchial smooth muscle (BSM) of allergic asthma. The ovalbumin (OA)-sensitized mice were repeatedly challenged with aerosolized OA to induce asthmatic reaction. Twenty-four hours after the last antigen challenge, the main bronchial smooth muscle (BSM) tissues were isolated. Tension study showed a BSM hyperresponsiveness to acetylcholine in the OA-challenged mice. Both quantitative RT-PCR and immunoblot analyses revealed a significant decrease in PAC1 receptor expression in BSMs of the diseased mice. Accordingly, in the antigen-challenged group, the PACAP-induced PAC1 receptor-mediated BSM relaxation was significantly attenuated, whereas the relaxation induced by vasoactive intestinal polypeptide was not changed. These findings suggest that the relaxation induced by PACAP is impaired in BSMs of experimental asthma due to a down-regulation of its binding partner PAC1receptor. Impaired BSM responsiveness to PACAP might contribute to the AHR in asthma.
Purpose: The baroreflex-mediated increase in heart rate (HR) in response to acute reduction of systolic blood pressure (SBP) was studied in order to assess whether the changes in arterial baroreflex sensitivity depend on the intensity of surgical stress, and location of visceral and somatic stimulation during surgery. Methods: Patients were divided into visceral stimulation groups [upper ( n --30) and lower (n = 30) abdominal surgery] and somatic stimulation groups [upper in = 25) and lower (n = 25) limbs, and chest wall (n = 25) surgery]. Acute hypotension as a baroreflex depressor test was induced by prostaglandin E~ (PGE,) 10 min before surgical incision (control) and during surgical manipulation under isoflurane-N20 anaesthesia or isoflurane-N20-fentanyl anaesthesia. Plasma level of ACTH was measured in an additional 40 patients who underwent upper abdominal surgery. Results: During upper abdominal surgery, the heart rate baroreflex sensitivity (AHR/ASBP) was depressed from -0.47 _+ 0.05 (control) to -0.01 _+ 0.04 (P < 0.05). The reflex heart rate baroreflex sensitivity remained unchanged and was similar among the remaining groups of patients. The concentration of ACTH increased from 12.5 -+ 1.0 (control) to 343 +-78.6 pg.ml-' (P < 0.05) with isoflurane-N20 anaesthesia but did not change with isoflu~ne-N20-fentanyl anaesthesia during upper abdominal surgery. Conclusion: Upper abdominal surgery is associated with the most stressful stimulation to attenuate heart rate baroreflex sensitivity. Integrity of the baroreflex can be preserved by adding opioids to supplement inhalation anaesthesia.Objectif : L~augmentation de la fr~quence cardiaque (FC) ~ m~diation baror~flexe en r~ponse ~ une diminution soudaine de la tension art&ielle systolique (-I-AS) a &~ ~tudi& dans le but d'~valuer si les changements de sensibilit~ art&ielle baror~flexe d~pendent de I'intensit~ du stress chirurgical et du si~ge de la stimulation visc&ale et somatique pendant la chirurgie. M&hode : Les patients ont ~t~ r~partis en diff6rents groupes : selon une stimulation visc&ale [chirurgie abdominale haute (n = 30) et basse ( n = 30)] et selon une stimulation somatique [chirurgie des membres sup6rieurs (n =25) et inf&ieurs (n = 25) ou chirurgie de la paroi thoracique (n = 25)]. Une hypotension soudaine, sous forme de test d~presseur baror~flexe, a ~t~ induite par la prostaglandine E, (PGE~) 10 rain avant I'incision chirurgicale (groupe t~moin) et pendant la manipulation chirurgicale sous anesth&ie avec isoflurane N20 ou sous anesth&ie avec isoflurane N20 et fentanyl. Le niveau plasmatique d'ACTH a ~t~ mesur~ chez 40 patients additionnels admis pour une chirurgie abdominale haute. R~sultats : Pendant la chirurgie abdominale haute, la sensibilit~ de la fr~quence cardiaque baror~flexe (AFC / ATAS) &ait abaiss~e de -0,47 _+ 0,05 (t~moin) ~ -0,01 + 0,04 (P < 0,05). La sensibilit~ r6flexe de la fr~quence cardiaque baror~flexe n'a pas chang~ et 6tait similaire parmi les autres groupes de patients. La concentration d'ACTH a augment~ de 12,5 -1,0 (t...
A case of primary trabecular carcinoid of the ovary apparently occurring from the foregut element of a mature cystic teratoma was reported. The tumor was found incidentally and resected surgically from a 56-year-old female. The cystic teratoma found in the tumor was composed of only respiratory epithelium except a colliculus which showed a picture of tonsil-like tissue. No thyroid tissue was found. The trabeculae of the tumor cells were longer and wavier near the cystic teratoma, while they were straight and short at the periphery. The tumor cells had argyrophil granules but negative in argentaffin granules. The electronmicroscopy revealed many round neurosecretory granules measuring from 170 to 290 nm in diameter. The histogenesis was also discussed. ACTA PATHOL. JPN. 37: 837-842, 1987.
Case ReportThe patient, a 56-year-old female, was admitted to our hospital in August 1982 for the management of a nonsymptomatic ovarian tumor found by sonography in a routine
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