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Yuwaraj K. Narnaware Bridget I. Baker Mike G. Tomlinson 《Fish physiology and biochemistry》1994,13(1):31-40
The effect of acute and chronic stress on the phagocytic activity of putative macrophages from the rainbow trout. Oncorhynchus mykiss has been assessed, using an in vitro phagocytic index, in which the average number of engulfed yeast cells in a population of phagocytes is determined. An injection
stress given under light anaesthesia, or a longer noise stress combined with confinement, both significantly reduced, within
3 h, the level of phagocytic activity of macrophages from the spleen and pronephros. Daily injection stress over six days
had a lesser effect on the proportion of phagocytically active cells even though plasma cortisol levels were equally raised.
Daily dexamethasone injection depressed the proportion of phagocytically active cells more than saline injection. In these
in vivo experiments, it was not possible to determine whether stress and steroids depressed the phagocytic activity of individual
macrophages or caused the active macrophages to migrate out of the spleen and pronephros. Administration of cortisol (200
nM) to trout macrophages in vitro failed to depress phagocytic activity within a 3h period but both α- and β-adrenergic agonists (10 μM) were usually depressive.
It is proposed that the autonomic nervous system may be an early regulator of macrophage phagocytosis following stress and
that corticosteroids only exert their suppressive effect on macrophage activity in the longer term.
To whom reprint requests should be addressed. 相似文献
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试验旨在研究精索上神经（superior spermatic nerve,SSN）对睾丸功能的影响,25只成年Wistar大鼠随机分为2组,试验组左右睾丸切除精索上神经,手术30 d后两组大鼠同时处死取样分析。结果显示,睾丸去精索上神经不影响睾丸指数的大小但使附睾尾精子数极显著降低（P＜0.01）,平均日增重显著增加（P＜0.05）。增殖细胞核抗原（PCNA）免疫组织化学染色结果显示,睾丸去精索上神经不影响曲细精管精原细胞和初级精母细胞的增殖,但影响曲细精管的形态和生殖细胞的规则排列。RT-PCR结果显示,睾丸去精索上神经明显上调β1AR mRNA的表达,下调β2AR mRNA的表达;另外切除精索上神经不影响睾丸3β-羟胆固醇脱氢酶（3β-HSD）mRNA表达,但显著抑制类固醇快速调节蛋白（StAR）、胆固醇侧链裂解酶（P450scc）mRNA表达（P＜0.05）。结果表明,支配睾丸的精索上神经通过调节肾上腺素能受体β1AR和β2AR的表达及StAR和P450scc影响睾丸睾酮的合成和精子的发生。 相似文献
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AIM: To determine the alterations of myocardial 1-adrenergic receptor (1-AR) and cardiac sympathetic norepinephrine transporter (NET) mRNA expression, which is upstream modulator of 1-AR, in rats with longterm volume overload (VOL). METHODS: Left ventricular systolic (LVSP) and end diastolic pressure (LVEDP) of rats with VOL induced by aortacaval fistula operation and control group were measured at 314,30and 60d after the operation, the mRNA at the time points was measured by RT-PCR and Northern blot analysis and quantified by densitometry. RESULTS: The cardiac sympathetic NET specific expression is in the cardiac sympathetic ganglia. Be compared with the control group, LVSP of VOL rats decreased most dramatically by 24% (P<0.05) at 3 d, after that LSVP increased gradually and were higher than control group at 60d. LVEDP increased initially compared with the control (P<0.05), the latter recovered to the control levels. RT-PCR and Northern blot showed that in VOL rats the NET mRNA did not decreased significantly from 3to 30d, and decreased remarkably at 60d after the operation (P<0.05). The pattern of 1-AR mRNA expression were similar to the NET. CONCLUSION: The results suggest decreased levels of NET mRNA may contribute to cardiac sympathetic dysfunction in heart failure due to longterm VOL, which may lead to decreased myocardial 1-AR mRNA. We conclude that the normal NET mRNA expression may play a critical role to maintain sensitivity of 1-AR to adrenergic stimuli and cardiac contractility. 相似文献
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Yumi MATSUSHITA Miki MANABE Issei KITAGAWA Masashi HIGUCHI Yoshinao Z HOSAKA Naoki KITAMURA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(10):1570
The activation of α2 adrenergic receptors contributes to analgesia not only in the central nervous system but also in the peripheral nervous system. We reported that noradrenaline inhibits the activity of transient receptor potential vanilloid 1 (TRPV1) evoked by capsaicin through α2 receptors in cultured rat dorsal root ganglion (DRG) neurons. However, it is unclear whether activation of TRPV1 expressed in peripheral nerve terminals is inhibited by α2 receptors and whether this phenomenon contributes to analgesia. Therefore, we examined effects of clonidine, an α2 receptor agonist, on several types of nociceptive behaviors, which may be caused by TRPV1 activity, and subtypes of α2 receptors expressed with TRPV1 in primary sensory neurons in rats. Capsaicin injected into hind paws evoked nociceptive behaviors and clonidine preinjected into the same site inhibited capsaicin-evoked responses. This inhibition was not observed when clonidine was injected into the contralateral hind paws. Preinjection of clonidine into the plantar surface of ipsilateral, but not contralateral, hind paws reduced the sensitivity to heat stimuli. Clonidine partially reduced formalin-evoked responses when it was preinjected into ipsilateral hind paws. The expression level of α2C receptor mRNA quantified by real-time PCR was highest followed by those of α2A and α2B receptors in DRGs. α2A and α2C receptor-like immunoreactivities were detected with TRPV1-like immunoreactivities in the same neurons. These results suggest that TRPV1 and α2 receptors are coexpressed in peripheral nerve terminals and that the functional association between these two molecules causes analgesia. 相似文献
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Lesley A. Zwicker Andrea R. Matthews Etienne Côté Erin Andersen 《Veterinary radiology & ultrasound》2016,57(3):230-236
Dexmedetomidine, an alpha2‐adrenergic agonist, may be used in companion animals for chemical restraint, including cardiac evaluation. Echocardiographic changes associated with alpha2‐adrenergic agonists have been described; however reports of radiographic changes in cats were not found at the time of this study. Aims of this observational, prospective, experimental study were to describe the effects of dexmedetomidine on the radiographic appearance of the cardiac silhouette in healthy, adult cats. Fourteen healthy adult cats received dexmedetomidine 40 mcg/kg IM. Right lateral, left lateral, ventrodorsal, and dorsoventral thoracic radiographs were obtained for each cat at three time points: presedation, intrasedation, and postsedation (≥ two hours after reversal with atipamezole). Radiographs were evaluated in a blinded, randomized fashion by two independent observers using the vertebral heart score on all four views, the number of intercostal spaces on lateral projections, and the percent width of thorax on ventrodorsal and dorsoventral projections. Median vertebral heart score on right lateral view was significantly increased intrasedation (median = 7.8; range = 7.25–8.25) compared to presedation (median = 7.5; range = 7–8 [P = 0.001]). Median percentage width was significantly higher intrasedation (70% on VD; range 65–80 [P = 0.001], and 75% on DV; range 65–80 [P = 0.006]) compared to presedation (65%; range 65–75 on both projections). Dexmedetomidine was associated with a small but significant increase in cardiac silhouette size on right lateral (vertebral heart score), ventrodorsal (percentage width), and dorsoventral (percentage width) radiographs in healthy adult cats. This effect should be taken into consideration for future interpretation of thoracic radiographs in dexmedetomidine‐sedated cats. 相似文献
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ObjectiveTo describe the pharmacodynamics and pharmacokinetics following an intravenous (IV) bolus dose of medetomidine in the horse.Study designProspective experimental trial.AnimalsEight, mature healthy horses age 11.7 ± 4.6 (mean ± SD) years, weighing 557 ± 54 kg.MethodsMedetomidine (10 μg kg?1) was administered IV. Blood was sampled at fixed time points from before drug administration to 48 hours post administration. Behavioral, physiological and biochemical data were obtained at predetermined time points from 0 minutes to 24 hours post administration. An algometer was also used to measure threshold responses to noxious stimuli. Medetomidine concentrations were determined by liquid chromatography-Mass Spectrometry and used for calculation of pharmacokinetic parameters using noncompartmental and compartmental analysis.ResultsPharmacokinetic analysis estimated that medetomidine peaked (8.86 ± 3.87 ng mL?1) at 6.4 ± 2.7 minutes following administration and was last detected at 165 ± 77 minutes post administration. Medetomidine had a clearance of 39.6 ± 14.6 mL kg?1 minute?1 and a volume of distribution of 1854 ± 565 mL kg?1. The elimination half-life was 29.1 ± 12.5 minutes. Glucose concentration reached a maximum of 176 ± 46 mg dL?1 approximately 1 hour post administration. Decreased heart rate, respiratory rate, borborygmi, packed cell volume, and total protein concentration were observed following administration. Horses lowered their heads from 107 ± 12 to 20 ± 10 cm within 10 minutes of drug administration and gradually returned to normal. Horse mobility decreased after drug administration. An increased mechanical threshold was present from 10 to 45 minutes and horses were less responsive to sound.Conclusion and clinical relevance Behavioral and physiological effects following intravenous administration positively correlate with pharmacokinetic profiles from plasma medetomidine concentrations. Glucose concentration gradually transiently increased following medetomidine administration. The analgesic effect of the drug appeared to have a very short duration. 相似文献