Correction: Shoaib et al. Neuroprotective Effects of Dried Tubers of Aconitum napellus. Plants 2020, 9, 356

We are sorry to report that some images in Figure 1 reported in our recently published paper [...].

Neuroprotective Effects of Dried Tubers of Aconitum napellus

The present study was designed to explore the neuroprotective properties of Aconitum napellus (Ranunculaceae). The plant detoxification was done using either water, or cow or goat milk as per the Ayurvedic shodhana method. The evaluation of the neuroprotective role of A. napellus was performed on diabetic neuropathy induced by streptozotocin in Sprague Dawley (SD) rats. Body mass, blood sugar level, oral glucose tolerance test, hyperalgesia, cold allodynia, motor co-ordination test, and locomotor activity, oxidative biomarkers (TBARS, reduced glutathione, catalase and superoxide dismutase) and sciatic nerve histomorphology were assessed. The in vitro studies were done on human neuroblastoma cell line SHSY-5Y and used an MTT assay to assess the antiproliferative activity of different extracts. Results suggest that the goat milk treated chloroform extract has less percentage of aconitine. After administration of the detoxified chloroform extract to the diabetic animals, there was a significant improvement in the myelination and degenerative changes of the nerve fibers along with behavioral changes (p < 0.05 as compared with diabetic control group). The findings of the in vitro research show an effective neuroprotective role of A. napellus. This suggests that A. napellus should be further investigated for its effect in diabetic pathology.

Beneficial effects of n-hexane bark extract of Onosma echioides L. on diabetic peripheral neuropathy

Onosma echioides Linn (Boraginaceae) is the most frequently used curative herb widely used for kidney obstruction, sciatic pain, and gout. The present study was designed to investigate the therapeutic effects of n-hexane bark extract of O. echioides (OE) L. root in vivo against Streptozotocin-induced diabetic neuropathy in SD rats. For in vivo activity, the experiment was categorized into five different groups (n = 5). Group-I was considered as nondiabetic/normal control (NC) treated with 0.5% carboxymethyl cellulose (CMC), Group II as diabetic control, Group-III, IV, and V served as diabetic treated with OE 50, OE 100, and pregabalin at a dose of 50, 100, and 10 mg/kg body weight, orally, respectively. Body weight, blood glucose, oral glucose tolerance test, behavioral studies (motor coordination test, thermal hyperalgesia, cold allodynia, locomotor activity, oxidative biomarkers (thio barbituric acid reactive substances [TBARS], superoxide dismutase [SOD], glutathione [GSH], and catalase), and histopathology of the sciatic nerve were performed. Treatment with OE showed a dose-dependent increase in neuroprotective activity by improving the myelination and decreasing the axonal swelling of nerve fibers. The verdicts of behavioral activities showed a remarkable effect on animals after the treatment of extract and standard drug pregabalin. In conclusion, our findings supported the traditional application of OE and explored its importance in the management of diabetic neuropathy. Additional clinical experiments may provide novel therapeutic drugs for diabetes and its complications.

Evaluation of hepatoprotective potential of Erythrina indica leaves against antitubercular drugs induced hepatotoxicity in experimental rats

BACKGROUND

Erythrina indica Lam. traditionally used in the treatment of laxative, diuretic, worm infestation, liver ailment and joints pain.

OBJECTIVE

To evaluate the antihepatotoxic potential of Erythrina indica against isoniazid (INH) and rifampicin (RIF) induced hepatotoxicity in rats.

METHODS AND MATERIAL

Liver toxicity was induced by antitubercular drugs (INH+ RIF) at dose level of 50 mg/kg each, p.o for 28 days. 50% methanolic extract of Erythrina indica (100 and 200 mg/kg) were administered orally once daily for 28 days. The hepatoprotective activity was assessed using various biochemical parameters SGOT, SGPT, ALP, bilirubin, total protein, albumin and LDH. Meanwhile, in vivo antioxidant activities as SOD, CAT, GSH and, LPO were measured in liver homogenate also histological examinations were carried out to assess hepatoprotective activity.

STATISTICAL ANALYSIS USED

The values were subjected to one way analysis of variance (ANOVA) followed by Tukey multiple compare test. Results were considered statistically significant when P < 0.05.

RESULTS

Obtained results demonstrated that the treatment with Erythrina indica (E. indica) significantly prevented drug induced increase in serum levels of hepatic enzymes. Furthermore, Erythrina indica significantly reduced the lipid peroxidation (P < 0.01 tp P < 0.001) in the liver tissue and restored activities of defense antioxidant enzymes GSH (2.15 ± 0.08 to 2.48 ± 0.99; P < 0.05), SOD (2.69 ± 0.752 to 3.712 ± 0.056; P < 0.05 to P < 0.01) and CAT (10.20 ± 0.58 to 12.59 ± 0.42; P < 0.05 to P < 0.001) towards normal. Histopathology of liver tissue showed that Erythrina indica attenuated the hepatocellular necrosis, regeneration and repair of cells toward normal.

CONCLUSION

The results of this study strongly indicate the protective effect of Erythrina indica against liver injury which may be attributed to its hepatoprotective activity, and there by scientifically support its traditional use.

Bromelain capped gold nanoparticles as the novel drug delivery carriers to aggrandize effect of the antibiotic levofloxacin

To develop bromelain capped gold nanoparticles (BRN capped Au-NPs) as the effective drug delivery carriers of the antibiotic levofloxacin (LvN) and evaluate antibacterial potential of its bioconjugated form compared to pure LvN. BRN capped Au-NPs were synthesized by in vitro method and bioconjugated to LvN using 1-ethyl-3-(3-dimethylamino-propyl)-carbodiimide as activator to form Au-BRN-LvN-NPs. These were characterized for mean particle size by dynamic light scattering analysis, zeta potential by Zetasizer nanosystem analysis and transmission electron microscopy (TEM) on carbon coated TEM copper grids by TEM respectively. Drug loading efficiency of LvN was calculated using UV-visible spectroscopy by standard curve of pure LvN. Antibacterial efficacy of Au-BRN-LvN-NPs and pure LvN was determined by evaluating minimum inhibitory concentration (MIC) against Staphylococcus aureus and Eschereschia coli. Two peaks were observed in Au-BRN-LvN-NPs spectrum one at 307 nm and other at 526 nm while one peak in BRN capped Au-NPs at 522 nm during UV spectroscopy suggesting red shift. The drug loading efficiency of LvN was found to be 84.8 ± 2.41 %. The diameter of Au-BRN-LvN-NPs and BRN capped Au-NPs were found to be (58.65 ± 2 nm, 38.11 ± 2 nm), zeta potential (-9.01 mV, -13.8 mV) and surface morphology (~13.2 nm, 11.4 nm) respectively. The MICs against S. aureus and E. coli were found to be (0.128 µg/mL, 1.10 µg/mL) for Au-BRN-LvN-NPs and (0.547 µg/mL, 1.96 µg/mL) for pure LvN. The results suggested that BRN capped Au-NPs can be used as effective drug delivery carriers of the antibiotic LvN. The Au-BRN-LvN-NPs exhibited enhanced antibacterial activity compared to pure LvN alone. (Graphical abstract see Figure 1(Fig. 1))

New 4'-substituted benzoyl-β-D glycoside from the fruit pulp of Terminalia belerica with antiplatelet and antioxidant potency

BACKGROUND

The fruit Terminalia belerica is a rich source of vitamins, acids, and nutraceuticals which have free radical scavenging activity. Thus, the ethanolic extract of fruit and its isolated compound (Tb-01) were intended to estimate antiplatelet and antioxidant activities.

METHODS

The ethanolic extract was submitted to Si-gel CC and the compound was isolated. The compound Tb-01 was characterized as benzoyl-β-D-(4'→10″ geranilanoxy)-pyranosides on the basis of spectral data [ultra violet (UV), infrared (IR), ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and Mass Spectroscopy] and chemical analyses. The ethanolic extract and Tb-01 at different concentrations were in vitro screened for antiplatelet and antioxidant activity. The antiplatelet activity was carried out by using platelet rich plasma prepared by centrifugation of rabbit whole blood (containing 0.9% sodium citrate as anticoagulant) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl, reducing power, and nitric oxide anion scavenging activity models.

RESULTS

The compound Tb-01 was an amorphous brownish powder, yield 0.64% (w/w), melting point 105-110 °C, Retardation factor/Retention Value (R _f value) at 0.42 in methanol:chloroform (20:80) solvent system, UV absorption maxima at 243 nm, and molecular peak [M + H]⁺ at 394.15 m/z. It was observed that the ethanolic extract and Tb-01 at different concentrations showed significant antiplatelet and antioxidant activity. The antioxidant activity, like scavenging of 1,1-diphenyl-2-picrylhydrazyl radicals, nitric oxide radical, and reductive power were found to be concentration-dependent and increased when increasing amounts of sample were used.

CONCLUSION

Mass spectra and ¹H NMR confirmed the isolated compound structure which was supported by ¹³C NMR and IR spectra. Tb-01could be promising for future applications in the treatment of blood clots, pulmonary embolism, and other related diseases.

Eupalitin induces apoptosis in prostate carcinoma cells through ROS generation and increase of caspase-3 activity

Prostate cancer is the second most common malignancy in the human reproductive system. Eupalitin is one of the O-methylated flavonol-exhibited enhanced cancer chemopreventive agents. The current study highlights the structural determination of eupalitin and aims to explore the antitumor activity of eupalitin in human prostate cancer cell (PC3) and its underlying mechanism. Eupalitin structure was determined by using FTIR, (1)H NMR, and (13)C NMR. PC3 cells were treated with increasing concentrations of eupalitin, followed by analysis of the cell viability with an MTT assay. The results demonstrated that eupalitin markedly inhibited the proliferation of PC3 cells in a concentration-dependent manner. The results from fluorescent microscopic analysis of nuclear condensation and intracellular ROS generation determined that eupalitin significantly induced ROS level lead to nuclear apoptosis. Cell cycle analysis revealed that eupalitin-induced cell cycle progression as a percentage of cells in G0/G1 phase decreased whereas S phase increased. Caspase-3 immunofluorescence analysis confirms the efficacy of eupalitin-inducing apoptotic pathway and cell death. Thus, our study is helpful in understanding the mechanism underlying these effects in prostate cancer and it may provide novel molecular targets for prostate cancer therapy.

Development and validation of an LC-MS/MS method for simultaneous determination of piperaquine and 97-63, the active metabolite of CDRI 97-78, in rat plasma and its application in interaction study

Piperaquine-dihydroartemisinin combination is the latest addition to the repertoire of ACTs recommended by the World Health Organization (WHO) for treatment of falciparum malaria. Due to the increasing resistance to artemisinin derivatives, CSIR-CDRI has developed a prospective short acting, trioxane antimalarial derivative, CDRI 97-78. In the present study, a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the simultaneous quantification of piperaquine (PPQ) and 97-63, the active metabolite of CDRI 97-78 found in vivo, was developed and validated in 100 μL rat plasma using halofantrine as internal standard. PPQ and 97-63 were separated using acetonitrile:methanol (50:50, v/v) and ammonium formate buffer (10 mM, pH 4.5) in the ratio of 95:5(v/v) as mobile phase under isocratic conditions at a flow rate of 0.65 mL/min on Waters Atlantis C18 (4.6 × 50 mm, 5.0 µm) column. The extraction recoveries of PPQ and 97-63 ranged from 90.58 to 105.48%, while for the internal standard, it was 94.27%. The method was accurate and precise in the linearity range 3.9-250 ng/mL for both the analytes, with a correlation coefficient (r) of ≥ 0.998. The intra- and inter-day assay precision ranged from 2.91 to 8.45% and; intra- and inter-day assay accuracy was between 92.50 and 110.20% for both the analytes. The method was successfully applied to study the effect of oral co-administration of PPQ on the pharmacokinetics of CDRI 97-78 in Sprague-dawley rats and vice versa. The co-administration of CDRI 97-78 caused significant decrease in AUC0-∞ of PPQ from 31.52 ± 2.68 to 14.84 ± 4.33 h*µg/mL. However, co-administration of PPQ did not have any significant effect on the pharmacokinetics of CDRI 97-78.

Evaluation of Cucurbita maxima extract against scopolamine-induced amnesia in rats: implication of tumour necrosis factor alpha

Cucurbita maxima (CM) seed oil is commonly used in Indian folk medicine to treat various ailments. We have investigated the effect of CM seed oil on memory impairment induced by scopolamine in rats. Male adult Wistar rats were administered scopolamine 1 mg/kg body weight, i.p. or 1.25 mg/kg body weight, s.c. to induce memory impairment. The nootropic agent piracetam 100 mg/kg body weight, i.p. and CM seed oil 100 and 200 mg/kg body weight, p.o. were administered daily for five consecutive days. The memory function was evaluated in the Morris water maze (MWM) test, the social recognition test (SRT), the elevated plus maze (EPM) test, and the pole climbing test (PCT). Acetylcholinesterase (AChE) activity and oxidative stress parameters were estimated in the cortex, hippocampus, and cerebellum of the brains after completion of the behavioural studies. The effects of scopolamine on the levels of the tumour necrosis factor alpha (TNF-α) transcript were also investigated. Scopolamine caused memory impairment in all the behavioural paradigms along with a significant increase in the AChE activity and oxidative stress in the brain. Scopolamine also caused a significant increase in the expression of TNF-α in the hippocampus. CM seed oil exhibited antiamnesic activity as indicated by a significant reduction in the latency time in the MWM test and decreased social interaction during trial 2 in the SRT. Further, treatment with CM seed oil significantly decreased the AChE activity and malondialdehyde levels and increased the glutathione level in brain regions. CM seed oil also significantly decreased the expression of TNF-α in the hippocampus. The effect of CM seed oil on behavioural and biochemical parameters was comparable to that observed in rats treated with piracetam. These results indicate that CM seed oil may exert antiamnesic activity which may be attributed to the inhibition of AChE and inflammation as well as its antioxidant activity in the brain.

Effect of methanolic extract of Asparagus racemosus Willd. on lipopolysaccharide induced-oxidative stress in rats

Lipopolysaccharide (LPS) induced oxidative stress and impairment of normal physiological function generally categorized by increased anxiety and reduced mobility. Therefore, the present study was to find out the effect Methanolic extract of Asparagus racemosus (MEAR ) in lipopolysaccharide (LPS)-induced oxidative stress in rats . LPS-induced oxidative stress in rats was measured by locomotor activity by photoactometer test, anxiety with elevated plus maze test and also studied the oxidative stress markers, nitric oxide and cytokines. The obtained data shows that LPS markedly exhausted (p<0.001) brain- reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) significantly increased (p<0.001) the level of malondialdehyde (MDA), nitric oxide and the activity of cytokines in the brain. MEAR supplementation resulted in normalization of brain GSH and CAT and SOD and decreases in the levels of MDA with reduction of nitric oxide and cytokines in the brain. The action of the extract at dose of 200 mg/kg was almost similar to the standard drug, quercetin (100mg/kg, p.o.). These present study conclude that MEAR administration significantly (P<0.05) reduced LPS- induced oxidative-stress and intensely suggest that Asparagus racemosus Willd. is a functionally newer type of cerebroprotective agent.

Effect of carbamazepine on the pharmacokinetic parameters of CDRI-97/78 following coadministration to rats

Coadministration of 2 or more drugs may result in unexpected toxicity. This study aimed to evaluate the effect of carbamazepine coadministration on the pharmacokinetics of CDRI-97/78, an 1,2,4-trioxane antimalarial agent. Firstly, 97/78 was administered alone and then 97/78 and carbamazepine were coadministered to male and female rats. An revalidated LC-MS/MS method was used for quantitation of 97/63 since 97/78 is instantly and completely converted to 97/63 (an in-vivo active metabolite). The Tmax and Cmax values of 97/63 were 1.75±0.77 h and 862±306 ng/mL in male rats whereas in female rats they were 5.45±0.76 h and 662.75±95.09 ng/mL after a single dose of 97/78 alone. However, following coadministration of 97/78 and carbamazepine, the values for Tmax and Cmax were 1.06±0.16 h and 533±153 ng/mL in male rats and 2.23±1.93 h and 636.5±112.4 ng/mL in female rats. The half life of 97/63 following a single oral dose of 97/78 or coadministration with carbamazepine to male rats was 6.98±0.63 h and 6.64±0.54 h, respectively; the values in female rats were 7.5±0.5 h and 5.48±0.37 h. A statistically insignificant difference (P>0.05) was observed with the student t-test for the pharmacokinetic parameters of 97/63 following oral administration of 97/78 alone or coadministration of 97/78 and carbamazepine except for MRT in female rats. Intersex statistical comparison also showed an insignificant difference for 97/63 following oral administration of 97/78 alone or in combination with carbamazepine except for MRT, which supports coadministration of 97/78 and carbamazepine.

Evaluation of cardioprotective effect of silk cocoon (Abresham) on isoprenaline-induced myocardial infarction in rats

OBJECTIVE

The study was conducted to evaluate cardioprotective effect of silk cocoon (Abresham) Bombyx mori (B. mori) on isoprenaline-induced myocardial infarction. This study deals with the cocoons, which is called Abresham in the Unani system of medicine. It is one of the 64 drugs which Avicenna has mentioned in Avicenna's tract on cardiac drugs and used in the treatment of cardiovascular diseases. Abresham is a chief ingredient of the two very famous Unani formulation viz. Khamira Abresham Sada, and Khamira Abresham Hakim Arshad Wala.

MATERIALS AND METHODS

The ethanolic extract of B. mori (Abresham) silk cocoons in the dose of 250 mg/kg and 500 mg/kg body weight was administered orally for 28 days before isoprenaline administration to test their cardioprotective effect. Isoprenaline (85 mg/kg) was administered subcutaneously on days 29(th) and 30(th), respectively in order to induce myocardial infarction.

RESULTS

The parameters for evaluation of cardioprotective activity were the physical parameters and the biochemical estimations. The physical parameters were gross examination of heart, heart weight/body weight ratio and histopathology examination. In biochemical estimations, the activity of various cardiac enzymes such as aspartate transaminase, alanine transaminase, creatinine kinase, lactate dehydrogenase, and the gold marker troponin-I were determined. The levels altered by isoproterenol were restored significantly by the administration of the both doses of test extract especially at higher dose.

CONCLUSION

The result of this study shows that alcoholic extract B. mori has significant cardioprotective activity against isoprenaline-induced myocardial infarction.

Intersex effect of lamotrigine on the pharmacokinetic parameters of CDRI-97/78, a novel trioxane antimalarial compound, in rats

Reports regarding drug toxicity and adverse events resulting from coadministration of multiple drugs are increasing at an alarming rate. CDRI-97/78 is an 1,2,4-trioxane antimalarial agent under development which gets metabolized to the in vivo active metabolite 97/63. In order to assess its drug interaction potential, CDRI-97/78 was administered alone and in combination with lamotrigine to male and female rats via the oral route. Quantification of the active metabolite 97/63 in rat plasma was achieved with an LC-MS/MS assay. After oral administration of 97/78, the Tmax and Cmax values of 97/63 in male rats were 1.75±0.77 h and 862±306 ng/mL while female rats showed values for Cmax of 622.75±95.09 ng/mL and for Tmax of 7.5±0.5 h. Coadministration of 97/78 and lamotrigine resulted in decreased Tmax and Cmax values in both male and female rats (Tmax and Cmax of 0.77±0.16 h and 58.58±6.43 ng/mL in male rats; 1.13±0.22 h and 62.95±12.00 ng/mL in female rats, respectively). A statistically significant difference (P<0.05) was observed for the pharmacokinetic parameters of 97/63 after oral administration of 97/78 alone and upon its coadministration with lamotrigine except for the Cmax and Tmax values in male and for the T1/2 value in female rats. Statistically, no significant difference for the pharmacokinetic parameters of 97/63 between male and female rats after oral administration of 97/78 alone or in combination with lamotrigine was determined except for Tmax. The study indicates that coadministration of 97/78, an antimalarial agent, and the antiepileptic lamotrigine may require dose adjustments. Additional clinical drug interaction trials may be required to confirm these findings.

Prediction of human absorption of a trioxane antimalarial drug (CDRI 99/411) using an in-house validated in situ single-pass intestinal perfusion model

OBJECTIVES

The aim of the study was to predict human intestinal permeability and the fraction absorbed of an oral dose of a promising trioxane anti-malarial drug (CDRI 99/411) using the single-pass intestinal perfusion technique (SPIP) in rats.

METHODS

Effective permeability coefficients (P eff) in anaesthetized rats were determined for marker compounds and the trioxane derivative 99/411. Drug solution in perfusion buffer was perfused through intestine with a flow rate of 0.2 ml/min and samples were taken from an outlet tubing at different time points up to 120 min. Drug concentrations in samples were determined using RP-HPLC.

KEY FINDINGS

The effective permeability coefficient values of marker compounds obtained in rats were compared with published data for human intestinal permeability (P eff (human)) and human fraction absorbed (F(a) (human)) to establish an in-house model. Strong correlations were found between rat and human values for markers (P eff (human) = 1.039 P eff (rat) - 0.1815; R2 = 0.970 and F(a) (human) = 0.15621n (P eff (rat) + 0.7232; R2 = 0.927). Subsequently the human permeability and fraction dose absorbed in human were predicted for 99/411 using the obtained rat permeability value and established correlations. P eff in human predicted from the model was found to be 7.05 x 10(-4) cm/s and F(a) value in human was predicted around 1.

CONCLUSIONS

Considering the high correlation of rat Peff values with those of human reported values, it can be concluded that the developed in-house model is reliable and can be used preliminarily, to predict human permeability and fraction dose absorbed of any test compound. From predicted results, 99/411 was found to have high permeability and possibly complete absorption in human.

Plasma renin activity and urinary kallikrein excretion in response to intravenous furosemide in diabetic patients

The responsiveness of renin-angiotensin and kallikrein-kinin systems to furosemide challenge has been investigated in forty-six diabetic patients (34 NIDDM/12 IDDM), subdivided into Group I (uncomplicated DM), Group II (DM with hypertension), Group III (DM with nephropathy), Group IV (DM with hypertension and nephropathy) and a control group of 10 healthy volunteers. Plasma renin activity (PRA) was estimated by radioimmunoassay in blood samples drawn before and 10 min after furosemide administration (0.5 mg/kg i.v.). Urinary kallikrein levels were measured by bioassay using estrogenized rat uterus preparation in 4h urine samples collected before and after the diuretic. Urinary Na+ and K+ were also measured. The basal PRA in diabetics was not significantly different from controls, whereas, urinary kallikrein levels were markedly low in all patients. Both PRA and kallikrein levels increased after furosemide in controls while in diabetics this response was severely blunted. In a subset of Group I, a paradoxical fall in PRA and kallikrein levels was noted after furosemide, an effect similar to that observed in patients with nephropathy (Group III). This response in absence of clinical and biochemical parameters of nephropathy indicates early derangement of renal hemodynamic mechanisms heralding the onset of nephropathy.

Increased brainstem angiotensin-I levels in chronic 2 KIC hypertensive rats

A study was undertaken on the role of brainstem renin-angiotensin system in maintenance of hypertension in chronic renovascular hypertensive rats. Hypertension was induced by unilateral renal artery clamping, while the contralateral kidney was left intact (2 KIC). Blood pressure (BP), plasma renin activity (PRA) and brainstem angiotensin (ang-I) levels were measured after 24 days, in hypertensive and sham-operated animals. In separate subgroups of these animals, the effect of intracerebroventricular administration of captopril on the parameters listed was studied. The results showed high ang-I levels in 2 KIC rats as compared to controls (P less than 0.05). Captopril administration (500 micrograms/50 microliters icv) caused a fall in BP and increase in brainstem ang-I levels (P less than 0.01). In control animals, however, captopril produced a rise in BP without any significant change in brainstem ang-I levels. Peripheral plasma renin activity was normal, despite significant sodium retention in 2 KIC rats. The results are suggestive of activation of brainstem renin-angiotensin system (RAS) in chronic 2 KIC hypertension.

Some aspects of pharmacological profile of sodium curcuminate

Rapid i.v. injection of sodium curcuminate (NaC) produced transient hypotension and bradycardia in anaesthetized dogs and cats which were not blocked by bilateral vagotomy, atropine, mepyramine or propranolol. In open-chest anaesthetized cats, decrease in blood pressure and heart rate was accompanied by simultaneous transient reductions in left ventricular systolic pressure, maximal rate of rise of left ventricular pressure and a concomitant increase in left ventricular end-diastolic pressure. It was concluded that the transient hypotensive effect of NaC is due to its myocardial depressant action. NaC exhibited negative inotropic and chronotropic effect on isolated perfused rabbit heart, an antispasmodic effect on smooth muscle of dog s intestine in vivo and of vas deferens of guinea-pig in vitro but no effect on the rectus abdominis muscle of frog or its response to cholinergic stimulation.

Nature of the beta-adrenoreceptors in the tracheal smooth muscle of the adult pig

Relaxant responses to isoprenaline (ISO), adrenaline (ADR) and noradrenaline (NA) were investigated on carbachol-contracted, isolated tracheal smooth muscle preparations of the adult pig to determine the nature of the beta-adrenoreceptors present. The order of relaxant potencies of the catecholamines on this preparation was ISO greater than ADR greater than NA. The potency ratio at 37 degrees C was 1:0.06:0.005. This suggests that beta 2-adrenoreceptors predominate in isolated tracheal smooth muscle of the adult pig. Though the order of potency for the above catecholamines did not change, at the lower temperatures of 29 degrees and 33 degrees C, the potency ratios were slightly modified to 1:0.0.98:0.004 and 1:0.07:0.004 respectively. pA2 values on pig tracheal smooth muscle were 8.65 and 9.13 respectively, for the non-selective beta-blockers propranolol and alprenolol, and 5.63, 5.20 and 6.26 respectively, for the beta 1 selective blockers practolol, atenolol and metoprolol and 6.82 for the beta 2 selective beta-blocker, H 35/25. The results suggest the existence and predominance of beta 2-adrenoreceptors in tracheal smooth muscle of the adult pig.

Anti-spasmogenic effect of cyproheptadine on guinea-pig ileum

Antagonistic activity of cyproheptadine against common spasmogens, like acetylcholine, histamine, serotonin, bradykinin and angiotensin, was studied on isolated guinea-pig ileum. Cyproheptadine produced a reversible antagonism of non-competitive type and was most effective against serotonin. It was less potent against histamine, bradykinin and angiotensin and least potent against acetylcholine.

Effect of beta-adrenergic blockers on isolated coronary arterial strip and tracheal smooth muscle of pig

Isolated coronary arterial strip and tracheal smooth muscle of pig, containing predominantly beta 1- and beta 2-adrenoceptors respectively, have been used for estimating the comparative potency of nine beta-adrenergic blocking agents. The order of potency of the antagonists on the isolated coronary arterial strip was propranolol greater than alprenolol greater than H 64/52 greater than H 64/55 greater than practolol greater than H 87/07 greater than atenolol greater than metoprolol greater than H 35/25, whilst the order of potency on the pig tracheal smooth muscle was alprenolol greater than propranolol greater than H 35/25 greater than H 87/07 greater than H 64/55 greater than H 64/52 greater than metoprolol greater than practolol greater than atenolol. Propranolol and alprenolol were almost equipotent in both the preparations and hence were nonspecific. Although practolol, metoprolol, H 64/55 and H 87/07 were beta 1-selective, their selectivity ratio was comparatively smaller than that of atenolol and H 64/52. The study indicates that H 64/52 and atenolol are the most specific beta-adrenergic blocking agents on isolated coronary arterial strip of pig and that their beta 1/beta 2-ratios are 126 and 120 respectively. H 64/52 like atenolol may be of therapeutic value in cardiovascular disorders.

Feline endotoxin shock: effects of methylprednisolone on kininogen-depletion, on the pulmonary circulation and on survival

1 Escherichia coli endotoxin, administered intravenously in a dose of 2 mg/kg to pentobarbitone anaesthetized, artificially ventilated cats resulted in pulmonary hypertension, systemic hypotension and an immediate (1-2 min) 30-40% reduction in plasma kininogen, an effect which probably indicates a release of plasma kinins. 2 Methylprednisolone (30 mg/kg), when administered 30 min before endotoxin, did not influence the endotoxin-induced pulmonary hypertension or systemic hypotension but completely prevented the depletion of plasma kininogen. 3 In spontaneously breathing cats, methylprednisolone, administered 30 min after endotoxin, caused a rapid repletion of kininogen and prolonged survival (47% at 6 h compared to 10% in the endotoxinalone animals). Methylprednisolone did not appear to influence lactate production or the hyperventilation observed during the delayed endotoxin shock phase. 4 It is concluded t,at methylprednisolone does not prevent the release, by endotoxin, of a pulmonary vasoconstrictor prostaglandin, or its effects, but that perhaps by preventing kinin release it may reduce endotoxin-induced capillary leakage.

Some effects of dihydroergocrisine and of phentolamine mesylate on renal function in rats

Single injections of dihydroergocristine (dhe) (25, 50 and 100 μg, i.p.) did not depress the systemic arterial pressure but antagonized the pressor effects of (-)-noradrenaline (100 μg, s.c.) in unanaesthetized rats. The effects of these doses of dhe on water diuresis were minimal: slight K retention, a rise in urinary Na:K and a slight but significant fall in the clearance of p-aminohippuric acid were noted. Single injections of phentolamine mesylate (10, 20 and 40 μg, i.p.) greatly depressed systemic arterial pressure and reduced the glomerular filtration rate and p-aminohippuric acid clearance and the excretion of water and Na proportionately, but markedly. The Na:K in the urine rose. Chemical denervation of the kidneys either with dhe, 32 μg, or phentolamine, 2 mg, thrice daily for 5–7 days decreased, but for 14 days increased, the juxtaglomerular index of the kidneys. Parallel changes were found in the extractable renin. Continued treatment with dhe (32 μg thrice daily for 2 weeks) raised, and hyperduric adrenaline (250 μg twice daily for 1 week) lowered the stores of growth hormone in the adenohypophysis. Continued treatment with dhe, 32 μg thrice daily produced antidiuresis and retention by the third day lasting to the fifth. This condition had reversed by the eighth day.