Modulation of neurological pathways by Salvia officinalis and its dependence on manufacturing process and plant parts used

Background

Salvia officinalis has been used successfully for the treatment of hot flushes and excessive sweating during menopause. However, modes of actions have not been elucidated conclusively. We explored its pharmacology beyond any hormonal activity with a focus on neurologic impulse transmission.

Methods

A hydroalcoholic, thujone-free extract from freshly harvested Salvia officinalis leaves (A.Vogel Menosan®) was investigated in an acetylcholinesterase enzyme assay and several receptor binding assays (adrenergic alpha 2A, GABA (benzodiazepine site), GABA_B; muscarinic M3, μ-opioid, serotonin 5-HT_1A, serotonin 5-HT_2B, serotonin 5-HT_2C and serotonin transporter). The influence of the manufacturing process on additional extracts from different fresh or dry plant parts was studied.

Results

The Salvia officinalis extract replaced 50% of specific ligand binding to GABA_A and GABA_B receptors at an inhibitory concentration (IC₅₀) of 89 and 229 μg/ml, respectively. Strong binding affinity was observed for the adrenergic α_2A receptor, μ-opioid receptors, muscarinic M3 receptors, and serotonin 5-HT_1A receptors, with IC₅₀ values of 15 μg/ml, 20 μg/ml, 25 μg/ml and 19 μg/ml, respectively. Moderate interference with 5-HT_2B, 5-HT_2C receptors, and the human serotonin transporter was found, all with IC₅₀ values above 32 μg/ml. Receptor binding data of Salvia extract were confirmed in native female hypothalamic tissue from two women (51 and 37 years old).

Use of freshly harvested Salvia leaves resulted in 2- to 4-fold higher activity/lower IC₅₀ values compared to extracts from dried plants or stipes.

Conclusion

Our results suggest potent modulation of neuro-receptors and of serotonin transporters as mode of action for Salvia officinalis alcoholic extract, which may normalize thermoregulation and possibly also mental impairment during menopause.

Brain concentrations of mGluR5 negative allosteric modulator MTEP in relation to receptor occupancy--Comparison to MPEP

BACKGROUND

To verify relation between brain free levels, receptor occupancy in vivo and in vitro affinity at the target for mGluR5 negative allosteric modulator (NAM) MTEP.

METHODS

We evaluated plasma and brain extra-cellular fluid (ECF) concentration of MTEP at behaviourally active dose (5mg/kg) using in vivo microdialysis. These values were compared it to the affinity in vitro (receptor binding and FLIPR) and to receptor occupancy in vivo. Another, related substance, MPEP was used for comparison.

RESULTS

MTEP and MPEP respectively inhibited mGluR5 receptors function in vitro with an affinity of 25.4 and 12.3 nM respectively. Accordingly peak ECF (extracellular fluid) levels were 1.3 and 0.14 μM, and peak total plasma levels were 7-11 and 2.6 μM. The ED50 for in vivo receptor occupancy was for both agents in the range of 0.8-0.7 mg/kg.

CONCLUSIONS

At behaviourally active dose MTEP produced complete mGluR5 receptor occupancy but over 50 times higher ECF concentrations than affinity for mGluR5 receptor in vitro. This difference is seems lower for other mGluR5 NAM compounds such as MPEP. A possibly explanation could be different distribution in body compartments of both agents leading to errors of estimation with the microdialysis technique or different pharmacological activity at the receptor.

The low-dose combination preparation Vertigoheel activates cyclic nucleotide pathways and stimulates vasorelaxation

Vertigo of various and often unknown aetiologies has been associated with and attributed to impaired microvascular perfusion in the inner ear or the vertebrobasilar system. Vertigoheel is a low-dose combination preparation of proven value in the symptomatic treatment of vertigo. In the present study we tested the hypothesis that Vertigoheel's anti-vertiginous properties may in part be due to a vasodilatory effect exerted via stimulation of the adenylate and/or guanylate cyclase pathways. Thus, the influence of Vertigoheel or its single constituents on synthesis and degradation of cyclic nucleotides was measured. Furthermore, vessel myography was used to observe the effect of Vertigoheel on the vasoreactivity of rat carotid arteries. Vertigoheel and one of its constituents, Anamirta cocculus, stimulated adenylate cyclase activity, while another constituent, Conium maculatum, inhibited phosphodiesterase 5, suggesting that the individual constituents of Vertigoheel contribute differentially to a synergistic stimulation of cyclic nucleotide signalling pathways. In rat carotid artery rings, Vertigoheel counteracted phenylephrine-induced tonic vasoconstriction. The present data demonstrate a vasorelaxant effect of Vertigoheel that goes along with a synergistic stimulation of cyclic nucleotide pathways and may provide a mechanistic basis for the documented anti-vertiginous effects of this combination preparation.

AWD 140-190: a potent anticonvulsant in the amygdala-kindling model of partial epilepsy

PURPOSE

Evaluation of the effect of the new anticonvulsant drug, AWD 140-190 [4-(p-bromophenyl)-3-morpholino-1H-pyrrole-2-carboxylic acid methyl ester] on focally induced seizures and on epileptogenesis in the kindling model.

METHODS

Effects of AWD 140-190 were studied in amygdala kindled rats after oral and intraperitoneal administration. In addition, the effect on kindling development was evaluated. In all experiments, behavioral changes in the rats in response to AWD 140-190 were monitored closely.

RESULTS

AWD 140-190 exerted potent anticonvulsant activity against focal seizures. After intraperitoneal and oral administration in fully kindled rats, the substance dose-dependently increased the threshold for induction of afterdischarges starting at 15 mg/kg. AWD 140-190 only weakly influenced the seizure severity of the animals after stimulation at the elevated afterdischarge threshold current. No adverse effects were observed up to 30 mg/kg after intraperitoneal and oral administration in the open field and in the rotarod test. No differences were found between kindled and nonkindled rats when comparing neurotoxicity of AWD 140-190. Prolonged treatment with AWD 140-190 during kindling acquisition did not prevent kindling, but significantly retarded the development of fully kindled seizures during the treatment.

CONCLUSIONS

This study demonstrates that AWD 140-190 has anticonvulsant effects in the amygdala kindling model in rats, suggesting that the substance is particularly effective against partial seizures. AWD 140-190 is orally active and devoid of neurotoxic effects in anticonvulsant doses, thus indicating that this compound has potential for antiepileptic therapy. AWD 140-190 retards the kindling development during the treatment. This effect could be explained by the acute anticonvulsant effect of the substance.

Expression of measles virus V protein is associated with pathogenicity and control of viral RNA synthesis

Nonstructural proteins encoded by measles virus (MV) include the V protein which is translated from an edited P mRNA. V protein is not associated with intracellular or released viral particles and has recently been found to be dispensable for MV propagation in cell culture (H. Schneider, K. Kaelin, and M. A. Billeter, Virology 227:314-322, 1997). Using recombinant MVs (strain Edmonston [ED]) genetically engineered to overexpress V protein (ED-V+) or to be deficient for V protein (ED-V-), we found that in the absence of V both MV-specific proteins and RNAs accumulated to levels higher than those in the parental MV molecular clone (ED-tag), whereas MV-specific gene expression was strongly attenuated in human U-87 glioblastomas cells after infection with ED-V+. The titers of virus released from these cells 48 h after infection with either V mutant virus were lower than those from cells infected with ED-tag. Similarly, significantly reduced titers of infectious virus were reisolated from lung tissue of cotton rats (Sigmodon hispidus) after intranasal infection with both editing mutants compared to titers isolated from ED-tag-infected animals. In cell culture, expression of V protein led to a redistribution of MV N protein in doubly transfected Cos-7 cells, indicating that these proteins form heterologous complexes. This interaction was further confirmed by using a two-hybrid approach with both proteins expressed as Gal4 or VP16 fusion products. Moreover, V protein efficiently competed complexes formed between MV N and P proteins. These findings indicate that V protein acts to balance accumulation of viral gene products in cell culture, and this may be dependent on its interaction with MV N protein. Furthermore, expression of V protein may contribute to viral pathogenicity in vivo.

7-Nitro indazole enhances methohexital anesthesia

7-nitro indazole, a selective inhibitor of the neuronal nitric oxide (NO) synthase dose-dependently prolongs the duration of methohexital narcosis in the rat. This effect can be antagonized stereoselectively by the NO-synthase substrate l-arginine (l-Arg). The results support the assumption that the potentiation of the anesthetic state by NO-synthase inhibitors is due to a specific effect on brain NO-synthase and a disruption of synaptic NO signalling pathways. These results are also in accordance with predictions that follow from recent hypotheses proposing that a modification of the NMDA receptor function is the final common pathway of anesthetic action.

AWD 140-190: a new anticonvulsant with a very good margin of safety

The anticonvulsant activity of the novel drug AWD 140-190 (4-(p-bromophenyl)-3-morpholino-1H-pyrrole-2-carboxylic acid methyl ester) was evaluated in animal models of epileptic seizures. AWD 140-190 was active at nontoxic doses after oral and intraperitoneal administration in rats and mice in a range of anticonvulsant tests. The compound was active against electrically-induced seizures (MES, ED50 rat p.o. = 2.47 mg/kg), in a genetic animal model the DBA/2 mouse, and in corneally kindled rats. It was not active against seizures induced chemically by pentylenetetrazole, bicuculline and strychnine. Effective doses in mice following both oral and intraperitoneal administration are similar indicating good oral absorption. During 14 days chronic oral treatment of mice with 10 mg/kg, no development of tolerance was observed. The protective indices (TD50/MES ED50) in rats and mice following oral administration are favorable when compared to phenytoin, carbamazepine and valproate. No motor impairment, evaluated with the rotarod test and by observation in the open field test, was observable following oral administration of doses up to 500 mg/kg. There was no influence on spontaneous motility and learning performance in rats and no interaction with ethanol in mice after administration of doses which are above anticonvulsant effective doses indicating the absence of central side effects. AWD 140-190 thus presents an orally active and safe anticonvulsant agent, which is structurally unrelated to anticonvulsants currently used.

D-23129: a potent anticonvulsant in the amygdala kindling model of complex partial seizures

The novel anticonvulsant drug D-23129 (N-(2-amino-4-(4-fluorobenzylamino)-phenyl) carbamic acid ethyl ester) was evaluated in the amygdala kindling model of complex partial seizures in rats. D-23129 exerts potent anticonvulsant activity against both focal and generalized seizures in animal models of epilepsy. After intraperitoneal and oral administration in kindled rats, the substance dose dependently increased the threshold for induction of afterdischarges, exerting significant effects already after 0.01 mg/kg. In higher doses (2.5-5 mg/kg i.p., 10-15 mg/kg p.o.) D-23129 also exerted anticonvulsant effects on other seizure parameters of amygdala-kindled rats, i.e. seizure severity, seizure duration, total duration of behavioural changes and afterdischarge duration. The adverse effects of D-23129 were quantitated in the open field and in the rotarod test, a standard test for motor impairment. D-23129 exerted no adverse effects on behaviour in doses up to 5 mg/kg i.p. and 15 mg/kg p.o. Comparing the adverse effects between kindled and non-kindled rats, no differences were found. The data demonstrate that D-23129 is more potent in the amygdala kindling model of complex partial seizures than in other seizure models. D-23129 is orally active and is devoid of neurotoxic effects in anticonvulsant doses, thus indicating that this compound has potential for antiepileptic therapy.

D-23129: a new anticonvulsant with a broad spectrum activity in animal models of epileptic seizures

The anticonvulsant activity of the novel drug D-23129 (N-(2-amino-4-(4-fluorobenzylamino)phenyl)carbamic acid ethyl ester) was evaluated in animal models of epileptic seizures. D-23129 was active after oral and intraperitoneal administration in rats and mice in a range of anticonvulsant tests at nontoxic doses. The compound was active against electrically induced seizures (MES, ED50 rat p.o. = 2.87 mg/kg), against seizures induced chemically by pentylenetetrazole (s.c. PTZ, ED50 mouse p.o. = 13.5 mg/kg), picrotoxin and N-methyl-D-aspartate (NMDA) and in a genetic animal model, the DBA/2 mouse. It was not active against seizures induced by bicuculline and strychnine. Motor impairment, evaluated with the rotarod test and by observation in the open field, was minimal at doses showing anticonvulsant activity. D-23129 was very effective in elevating the threshold for electrically and chemically induced seizures. Considering the dose increasing the MES threshold by 50% (TID50 mouse i.p. = 1.6 mg/kg; TID50 rat i.p. = 0.72 mg/kg) and the TD50 obtained in the rotarod test, the protective index of D-23129 is better than that of valproate and phenytoin. During 14 days chronic oral treatment with 15 mg/kg, no development of tolerance was observed. D-23129 thus presents an orally active, safe, broad spectrum anticonvulsant agent, which is structurally unrelated to anticonvulsants currently used. We expect that D-23129 will improve the treatment of refractory seizures in humans.

The natural history of intimal flaps in a canine model

The natural history of arterial intimal flaps has not been well defined. This study characterizes the natural history of unrepaired intimal flaps. Thirty-nine 1-, 2-, and 3-mm hemispheric, distally based intimal flaps were made in 4- to 5-mm diameter canine femoral and carotid arteries. Twenty arteries had 2- and 3-mm intimal flaps and were monitored for short-term arterial thrombosis and flap extension. Nineteen had 1- and 2-mm intimal flaps and were monitored for thrombosis, long-term development of neointimal hyperplasia, arterial stenosis, and persistence of the flap. While 40% of the arteries with 3-mm intimal flaps developed thrombosis in 3 to 5 days, only 3% of the arteries with 1- or 2-mm intimal flaps developed thrombosis. Most 1- to 2-mm intimal flaps resolved and the subsequent development of neointimal hyperplasia or arterial stenosis was minimal. Arteries with hemodynamically significant stenoses from intimal flaps warrant repair, while arteries with smaller intimal flaps may not require repair.

Studies with crystalline insulin from obese and lean mice of the BL/6J strain

Crystalline insulin was extracted and purified from the pancreases of obese (BL/6J/-ob/ob) and lean mice (BL/6J and BL/6J-ob/+). The two insulin preparations were compared with respect to their radioimmunologic properties as well as their ability to stimulate glucose metabolism in rat epididymal adipocytes and epididymal adipose tissue from obese and lean mice. No significant differences could be seen between the two insulin preparations and thus an insulin of altered biological properties is not likely to be an adequate explanation for the symptoms observed in the obese mouse.