The role of nitric oxide and l-type calcium channel blocker in the contractility of rabbit ileum in vitro

Nitric oxide (NO) and calcium channel blockers are two agents that can affect gastrointestinal motility. The goal of this work was to study the rabbit intestinal smooth muscle contraction response to (1) sodium nitroprusside (SNP), the NO donor, and its potential mechanism of action, and (2) nifedipine, the l-type Ca²⁺ channel blocker; to clarify the degree of participation by extra- and intracellular Ca²⁺ in smooth muscle contraction. We used standard isometric tension and intracellular micro-electrode recordings. To record the activity of the longitudinal smooth muscle of the ileum, segments of 1.5?cm length of the ileum were suspended vertically in organ baths of Krebs solution. The mechanical activity of the isolated ileal longitudinal muscle was recorded. Different substances were added, and the changes produced on spontaneous contraction were recorded. We found that SNP produced significant decrease, while nitric oxide synthase inhibitor produced significant increase in the amplitude of spontaneous contractions. Both apamin, the Ca²⁺-dependent K⁺ channel blocker, and methylene blue, the inhibitor of soluble guanylate cyclase, alone, partially decreased relaxation induced by SNP. Addition of both methylene blue and apamine together abolished the inhibitory effect produced by SNP on spontaneous contractions. Nifedipine produced significant decrease in the amplitude of spontaneous contractions. In conclusion, in longitudinal muscle of rabbit ileum, calcium channels blocker are potent inhibitors of spontaneous activity. However, both extracellular and intracellular Ca²⁺ participates in the spontaneous contractions. NO also has inhibitory effect on spontaneous activity, and this effect is mediated by cGMP generation system and Ca²⁺-dependent K⁺ channels.     

Formation of gap junctions by treatment in vitro with potassium conductance blockers

Gap junctions were regularly seen in thin sections of canine tracheal smooth muscle incubated in vitro. Their number was increased in tissued exposed in vitro to either of two potassium conductance blockers, tetraethylammonium (TEA) and 4-aminopyridine (4-AP), and at the same time the muscles became mechanically active, with spontaneous contractions. The presence of gap junctions in this smooth muscle may provide one basis for cell-to-cell coupling, and their increase after TEA- and 4-AP-treatment could account for a decreased junctional resistance between cells, contributing to a longer space constant. However, an increase in gap junctions was not sufficient to change the behavior of trachealis smooth muscle from multiunit to single-unit type. Gap junctions in increased numbers persisted after washout of 4- AP, which caused inhibition of spontaneous contractions, and despite inhibition of the contractile effects of 4-AP by atropine. The rapid induction of gap junction formation was not dependent on de novo synthesis of protein. The fact that the number of gap junctions can be increased by chemical agents has important implications for control of their formation and provides a tool for analysis fo their role in cell- to-cell coupling.     

An evaluation of three anaesthetic regimes in the gray short-tailed opossum (Monodelphis domestica)

The effect of several anaesthetic agents on the gray short-tailed opossum (Monodelphis domestica) was investigated. Pentobarbitone sodium at a dose of 50 mg/kg sedated the animals but did not produce analgesia or anaesthesia. A combination of ketamine hydrochloride and xylazine at 40 mg/kg and 5 mg/kg, respectively, sedated the animals, but anaesthetic levels were not attained. Halothane was most effective in producing anaesthesia in Monodelphis domestica. Hypothermia was a major side effect with all three anaesthetic regimes.     

Regulation of the Expression of Acetylcholinesterase by Muscular Activity in Avian Primary Cultures

Primary cultures of avian muscle cells express both globular and asymmetric molecular forms of acetylcholinesterase (AChE) when grown in a simple defined culture medium. Under these conditions, we analyzed the role of various agents interfering with muscular activity: tetrodotoxin (TTX) and veratridine, as well as a depolarizing concentration of KCl. These treatments caused the complete cessation of contractions in mature myotubes. We observed no influence on cellular AChE activity. The paralyzing treatments induced different effects on AChE secretion: TTX increased the secretion by approximately 25%, whereas KCl and veratridine reduced it by approximately 30%. The proportions of secreted molecular forms (mostly hydrophilic G4 and G2) were not modified significantly. TTX did not affect the pattern of molecular forms of cellular AChE (in particular, the proportion of A forms was not changed). Depolarization by veratridine or KCl induced an increase in the proportion of A forms in mature myotubes by a factor of 2-3. Similar results were obtained with quail myotubes cultured under the same conditions. This study shows that, in avian muscle cultures, the ionic balance across myotube membranes, rather than muscular activity per se, can regulate the level of A forms and the rate of AChE secretion. These results do not exclude the possible involvement of other factors, such as Ca2+ and/or peptidic factors. In addition, taking together our results and data from the literature. we conclude that the expression of AChE molecular forms depends both on the species and on the culture conditions used.     

Do β3-adrenergic receptors play a role in guinea pig detrusor smooth muscle excitability and contractility?

In many species, β3-adrenergic receptors (β3-ARs) have been reported to play a primary role in pharmacologically induced detrusor smooth muscle (DSM) relaxation. However, their role in guinea pig DSM remains controversial. The aim of this study was to investigate whether β3-ARs are expressed in guinea pig DSM and to evaluate how BRL37344 and L-755,507, two selective β3-AR agonists, modulate guinea pig DSM excitability and contractility. We used a combined experimental approach including RT-PCR, patch-clamp electrophysiology, and isometric DSM tension recordings. β3-AR mRNA message was detected in freshly isolated guinea pig DSM single cells. BRL37344 but not L-755,507 caused a slight decrease in DSM spontaneous phasic contraction amplitude and frequency in a concentration-dependent manner. In the presence of atropine (1 μM), only the spontaneous phasic contractions frequency was inhibited by BRL37344 at higher concentrations. Both BRL37344 and L-755,507 significantly decreased DSM carbachol-induced phasic and tonic contractions in a concentration-dependent manner. However, only BRL37344 inhibitory effect was partially antagonized by SR59230A (10 μM), a β3-AR antagonist. In the presence of atropine, BRL37344 and L-755,507 had no inhibitory effect on electrical field stimulation-induced contractions. Patch-clamp experiments showed that BRL37344 (100 μM) did not affect the DSM cell resting membrane potential and K(+) conductance. Although β3-ARs are expressed at the mRNA level, they play a minor to no role in guinea pig DSM spontaneous contractility without affecting cell excitability. However, BRL37344 and L-755,507 have pronounced inhibitory effects on guinea pig DSM carbachol-induced contractions. The study outlines important DSM β3-ARs species differences.     

Pharmacological basis for the use of turmeric in gastrointestinal and respiratory disorders

This study was carried out to provide scientific basis for the medicinal use of turmeric (Curcuma longa) in gastrointestinal and respiratory disorders. The crude extract of turmeric (Cl.Cr), relaxed the spontaneous and K+ (80 mM)-induced contractions in isolated rabbit jejunum as well as shifted the CaCl2 concentration-response curves. In rabbit tracheal preparation, Cl.Cr inhibited carbachol and K(+)-induced contractions. In anesthetized rats, Cl.Cr produced variable responses on blood pressure with a mixture of weak hypertensive and hypotensive actions. In rabbit aorta, Cl.Cr caused a weak vasoconstrictor and a vasodilator effect on K+ and phenylephrine-induced contractions. In guinea-pig atria, Cl.Cr inhibited spontaneous rate and force of contractions at 14-24 times higher concentrations. Activity directed fractionation revealed that the vasodilator and vasoconstrictor activities are widely distributed in the plant with no clear separation into the polar or non-polar fractions. When used for comparison, both curcumin and verapamil caused similar inhibitory effects in all smooth muscle preparations with relatively more effect against K(+)-induced contractions and that both were devoid of any vasoconstrictor effect and curcumin had no effect on atria. These data suggest that the inhibitory effects of Cl.Cr are mediated primarily through calcium channel blockade, though additional mechanism cannot be ruled out and this study forms the basis for the traditional use of turmeric in hyperactive states of the gut and airways. Furthermore, curcumin, the main active principle, does not share all effects of turmeric.     

Immunomagnetic enrichment of interstitial cells of Cajal

Disruptions of networks of interstitial cells of Cajal (ICC), gastrointestinal pacemakers and mediators of neurotransmission, can lead to disordered phasic contractions and peristalsis by reducing and uncoupling electrical slow waves. However, detailed analysis of the ICC network behavior has been hampered by their scarcity, limited accessibility in intact tissues, and contamination with other cell types in culture. Our goal was to develop a simple technique to purify ICC from murine gastrointestinal muscles for functional studies. We identified ICC in live small intestinal muscles or primary cell cultures by Kit immunoreactivity using fluorescent antibodies. Because this technique also labels resident macrophages nonspecifically, parallel studies were performed in which nonfluorescent Kit antibodies and macrophages labeled with fluorescent dextran were used for subtractive analysis of ICC. In both groups, Kit-positive cells were tagged with superparamagnetic antibodies and sorted on magnetic columns. Efficacy was assessed by flow cytometry. ICC enrichment from primary cultures and freshly dissociated tissues was approximately 63-fold and approximately 8-fold, respectively. Unlike the cells derived directly from tissues, cells sorted from cultures frequently yielded extensive, nearly homogenous ICC networks on reseeding. Monitoring oscillations in mitochondrial Ca(2+) or membrane potential by imaging revealed spontaneous rhythmicity in these networks. Cells that did not bind to the columns yielded cultures that were depleted of ICC and dominated by smooth muscle cells. In conclusion, immunomagnetic sorting of primary cultures of ICC results in relatively homogenous, functional ICC networks. This technique is less suitable for obtaining ICC from freshly dispersed cells.     

Stimulation of tissue plasminogen activator production from epithelial cell lines

The aim of this study was to investigate the possibility of enhancing the yield of tissue plasminogen activator (tPA) from two epithelial cell lines of normal (non-malignant) derivation grown in tissue culture. The three agents used in this investigation were chosen because of their proven enhancing effect on analogous cells or products. The anabolic hormone stanozolol was found to have no significant stimulatory effect on these cell lines. A phorbol acetate (12-O-tetradecanoylphorbol 13-acetate) caused a twofold enhancement in tPA yield but the most significant results were obtained with 5-azacytidine. This agent increased the yield by up to fourfold in small stationary cultures and threefold in large-scale microcarrier cultures. A combination of azacytidine and phorbol acetate did not have an additive effect on total yield but did alter the kinetics of tPA expression with time. Indications were that the maximum yield with these types of potentiating agents was achieved as it could not be increased by using a combination of two different agents.     

Thiopental inhibits nitric oxide production in rat aorta

We studied whether thiopental affects endothelial nitric oxide dependent vasodilator responses and nitrite production (an indicator of nitric oxide production) elicited by acetylcholine, histamine, and A23187 in rat aorta (artery in which nitric oxide is the main endothelial relaxant factor). In addition, we evaluated the barbiturate effect on nitric oxide synthase (NOS) activity in both rat aorta and kidney homogenates. Thiopental (10-100 microg/mL) reversibly inhibited the endothelium-dependent relaxation elicited by acetylcholine, histamine, and A23187. On the contrary, this anesthetic did not modify the endothelium-independent but cGMP-dependent relaxation elicited by sodium nitroprusside (1 nM - 1 microM) and nitroglycerin (1 nM - 1 microM), thus excluding an effect of thiopental on guanylate cyclase of vascular smooth muscle. Thiopental (100 microg/mL) inhibited both basal (87.8+/-14.3%) and acetylcholine- or A23187-stimulated (78.6+/-3.9 and 39.7+/-5.6%, respectively) production of nitrites in aortic rings. In addition the barbiturate inhibited (100 microg/mL) the NOS (45+/-4 and 42.8+/-9%) in aortic and kidney homogenates, respectively (measured as 14C-labeled citrulline production). In conclusion, thiopental inhibition of endothelium-dependent relaxation and nitrite production in aortic rings strongly suggests an inhibitory effect on NOS. Thiopental inhibition of the NOS provides further support to this contention.     

Action of veratridine on acetylcholinesterase in cultures of rat muscle cells

Studies on cultures of embryonic rat muscle cells have suggested that the presence of collagen-tailed forms may be correlated with spontaneous contractile activity: these forms disappear in the presence of tetrodotoxin which blocks the sodium channels involved in the propagation of action potentials. The effect of veratridine, a drug which maintains the sodium channels in the open state, was studied. It is shown here that in young cultures veratridine provoked a dramatic increase in total acetylcholinesterase activity and changed the distribution of the molecular forms of the enzyme, increasing the proportion and absolute amount of the A12 form. In order to elucidate the mechanism of action of this drug, the effects of various ions, ionophores, or other agents that modify the ionic permeabilities of membranes were also investigated.     

Tianeptine's effects on spontaneous and Ca2+-induced uterine smooth muscle contraction

Tianeptine is a novel anti-depressant with an efficacy equivalent to that of classical anti-depressants. Additional beneficial effects include neuroprotection, anti-stress and anti-ulcer properties whose molecular mechanisms are still not completely understood but may involve changes in the anti-oxidant defence system. Herein, we have studied the effects of tianeptine on both contractile activity of isolated rat uteri and components of the endogenous anti-oxidative defence system. Tianeptine-induced dose-dependent inhibition of both spontaneous and Ca2+-induced contraction of uterine smooth muscle. The effect was more pronounced in the latter. Tianeptine treatment increased glutathione peroxidase (GSH-Px) and catalase (CAT) activities in spontaneous and Ca2+-stimulated uteri. A significant decrease in glutathione-reductase (GR) activity in both spontaneous and Ca2+-induced uterine contractions after tianeptine treatment indicated a reduction in reduced glutathione and consequently a shift toward a more oxidised state in the treated uteri. In spontaneously contracting uteri, tianeptine caused a decrease in copper-zinc SOD (CuZnSOD) activity. Tianeptine's anti-depressant effects may be accomplished by triggering a cascade of cellular adaptations including inhibition of smooth muscle contractility and an adequate anti-oxidative protection response.     

Pharmacology of Acorus calamus L

Water soluble dried powder of alcoholic extract of roots and rhizomes of A. calamus L. was used. The in vivo experiments involved strychnine convulsant activity in frogs, spontaneous motor activity and amphetamine hyperactivity in mice, pentobarbitone sleeping-time in rats and local anaesthetic activity in guinea pigs and rabbits. Frog skeletal muscle and heart preparations and rat phrenic nerve diaphragm constituted the in vitro experiments. Plant extracts at 10, 20 mg/kg ip did not afford protection to strychnine (1,5,2.5 mg/kg) induced convulsions and same effect was found on acetylcholine induced contractions of rectus muscle except that it inhibited caffeine citrate contractions in frog. At 1, 10 and 100 micrograms/ml doses, it caused negative iono- and chronotropic effects in frogs. Dosages of 10, 25, 50 mg/kg ip of herbal extract antagonize spontaneous motor activity and also amphetamine induced hyperactivity in mice. It was less potent than chloropromazine, though exerts sedative and tranquilizing action. Local anaesthetic activity was found to be absent at 0.5 and 1% dose levels.     

Glucagon and choleragen stimulation of glycogenolysis in primary cultures of adult rat liver parenchymal cells: Lack of involvement of the glucocorticoids

The influence of glucagon, choleragen, and the adrenal glucocorticoids on glycogenolysis in primary cultures of adult rat liver parenchymal cells has been studied. Both glucagon and choleragen caused a twofold to threefold stimulation of glucose production from endogenous reserves of glycogen. The effect of glucagon on glucose production was noted at the earliest time point examined and the stimulation of glucose production was preceded by an elevation of cyclic AMP. Choleragen did not produce a significant stimulation of glucose production until 45 minutes after addition of the agent. Choleragen effects on glucose production were preceded by an elevation of cyclic AMP, but in contrast with glucagon, choleragen did not significantly elevate cyclic AMP until 30 minutes after addition to the culture. One ng of choleragen per ml of medium was sufficient to produce an effect on glucose production. Glucagon- or choleragen-treated cultures mobilized glycogen more rapidly than did untreated cultures incubated in glucose-free medium. In addition, both agents produced a stong inhibition of lactate production. Thus, the stimulation of glucose production by these agents was partially due to increased glycogen mobilization and partially due to redirection of carbon units from glycolysis. That glucose production in the hepatocytes is regulated in part by a cyclic AMP-dependent mechanism is strongly supported by the observation that both agents elevate cyclic AMP and cause an increase in glucose production and inhibition of lactate production. The possibility that the glucocorticoids participated in the regulation of glycogenolysis either in a direct or indirect (permissive) fashion was assessed. It was found that when the direct effect of the glucocorticoids on glycogenesis was taken into account, the glucocorticoids had no direct effects on glycogenolysis, nor did they alter the stimulation of glycogenolysis by glucagon or choleragen.     

Amiloride inhibits contraction and serotonin modulation of Aplysia muscle

1. Serotonin (5-HT) potentiates acetylcholine (ACh)-elicited contractions of Aplysia buccal muscles. Serotonin potentiation was significantly reduced by 0.03 mM, 0.1 mM, and 0.3 mM amiloride. 2. Unpotentiated ACh-elicited contractions were significantly reduced by 0.1 mM and 0.3 mM amiloride. 3. Amiloride reduced ACh-elicited depolarization. The reduction in contraction caused by 0.3 mM amiloride (to 16% of control) was larger than could be explained by the reduction in depolarization (86% of control). 4. Amiloride had no effect on tension in skinned muscle fibers, indicating that amiloride probably did not have a direct effect on contractile mechanisms. 5. Potentiation of contraction produced by zero sodium (Tris substituted, 0 Na-Tris) medium could be abolished by 0.3 mM amiloride. 6. Zero Na-Tris increased 45Ca influx 2.7-fold. In the presence of 0.3 mM amiloride, 0 Na-Tris increased 45Ca influx only 1.4-fold. 7. Amiloride (0.3 mM) reduced the elevation of muscle cAMP caused by 10(-6) M 5-HT by 60%. Zero Na-Tris did not cause a change in muscle cAMP.     

Cyclo-oxygenase blockers influence the effects of 15-lipoxygenase metabolites of arachidonic acid in isolated canine blood vessels

In canine saphenous veins both the 15-hydroxy- and 15-hydroperoxy derivatives of arachidonic acid, 15HETE and 15HPETE, caused endothelium-independent contractions which were not affected by a variety of classical receptor antagonists. These contractions were markedly augmented by cyclooxygenase blockers; nifedipine, which did not influence the contractions induced by lipoxygenase products, inhibited the potentiating effect of indomethacin. In the veins, 15HETE and 15HPETE also induced spontaneous rhythmic contractions which persisted after several washings but could be blocked by inhibitors of cyclooxygenase. In coronary, splenic, renal and femoral arteries, 15HETE and 15HPETE caused contractions which were also augmented by indomethacin and were dependent on the influx of extracellular calcium as they were inhibited by verapamil. Both 15-lipoxygenase metabolites evoked relaxations during contractions induced by prostaglandin F2 alpha or the thromboxane-mimetic U46619. These relaxations were not endothelium-dependent but were inhibited by indomethacin; they did not occur when the initial contractions were caused by K+, norepinephrine or 5-HT. Our results illustrate multiple vascular actions of 15HETE and 15HPETE in dog blood vessels.     

The survival of skeletal muscle myoblasts in vitro is sensitive to a donor of nitric oxide and superoxide, SIN-1, but not to nitric oxide or peroxynitrite alone.

The survival of skeletal muscle myoblasts in culture after exposure either to a donor of NO, sodium nitroprusside (SNP), or ethanamine, 2,2'-(hydroxynitrosohydrazono)bis-(DETA NONOate), or to a donor of both NO and O(-)(2), 3-morpholinosydnonimine hydrochloride (SIN-1), was investigated. SIN-1 reduced clonogenic survival markedly but donors of NO alone did not. The injurious effect of SIN-1 was prevented by oxyhemoglobin or by uric acid but not by superoxide dismutase. The exposure of myoblasts to authentic peroxynitrite (ONOO(-)) or to DETA NONOate in the presence of an O(-)(2)-generating system did not reduce their survival. The results show that NO or ONOO(-) alone is not detrimental to myoblast survival and suggest that SIN-1 toxicity is, at least in part, mediated by H(2)O(2) in this myoblast culture system.     

Effects of activated neutrophils on isolated rings of rat thoracic aorta

Local inflammation and respiratory burst of polymorphonuclear leukocytes generate reactive oxygen species (ROS). The aim of our study was to analyze the effects of peritoneal neutrophils on changes of the muscle tension of isolated aorta and compare their effects with those of different ROS. While native neutrophils did not influence muscle tension, the N-formyl-methionyl-leucyl-phenylalanine activated ones evoked a biphasic response on the KCl-precontracted aorta. The effects of activated neutrophils were in both respects similar to those evoked by xanthine/xanthine oxidase (X/XO) and differed from the effects evoked by H(2)O(2) and Fe(2)SO(4)/H(2)O(2). Using H(2)O(2) we demonstrated that the effects of ROS were dependent on the KCl induced initial tension. To exclude the effect of extensive depolarization the action of different ROS was studied also on tissues precontracted by phenylephrine. Under such condition activated neutrophils caused a marked contraction similar to that evoked by X/XO. Their effects differed however, from those of H(2)O(2) and Fe(2)SO(4)/ascorbic acid. These findings and elimination of activated neutrophil-induced contractions as well as the chemiluminiscence by superoxide dismutase suggest that the primarily activated neutrophil-released ROS was superoxide, which can be transformed to peroxynitrite, and other ROS including H(2)O(2). Reduction of all followed-up contractions caused by nordihydroguaiaretic acid, indicate that 5-lipoxygenase metabolites unselectively reduce contractions. In contrast, selective inhibition of activated neutrophil-evoked contraction by indomethacin suggests that cyclooxygenase metabolites are involved mainly in their action on vascular smooth muscle.     

Evidence for L-glutamate as a transmitter substance of motoneurons innervating squid chromatophore muscles

Motor nerve branches were stimulated in the dermis layer prepared from isolated pieces of dorsal mantle skin of the squid Lolliguncula brevis and the contractions of chromatophore muscle fibers were recorded with the aid of a photo-electric transducer. L-Glutamate (L-Glu), kainate and quisqualate caused a contracture and often repetitive twitch-like contractions. These effects were readily reversible. In the case of L-Glu application, twitches induced by single stimuli applied to motor nerves were enhanced and prolonged. The glutamate antagonists glutamic acid gamma-methyl ester, glutamic acid diethyl ester, D,L-2-amino-4-phosphonobutyrate and gamma-D-glutamylglycine prevented both nerve induced and L-Glu induced contractions. The NMDA-receptor agonists N-methyl-D-aspartate, L-aspartate and D-glutamate, and their antagonists alpha-aminoadipate and D,L-2-amino-5-phosphonovalerate were found ineffective. With the aid of saline media of different Ca and Mg content, it was possible to selectively eliminate one or all components of the effect of L-Glu. Tetrodotoxin abolished nerve induced contractile responses but did not interfere with the contracture caused by L-Glu. Intracellular electrical recording indicated that nerve stimulation causes EPSPs which do not give rise to spike discharges. The results are compatible with the hypothesis that L-Glu is a transmitter substance of the motoneurons that innervate chromatophore muscle fibers.     

Cellular and Secreted Forms of Acetylcholinesterase in Mouse Muscle Cultures

When grown in primary cell culture in the absence of neurons, muscle cells from a variety of species synthesize several forms of acetylcholinesterase (AChE), including the collagen-tailed A12 form. A12 AChE has been the subject of much study because it is thought to be a major functional enzyme form normally found in the basal lamina at the neuromuscular junction. In this paper, we show that muscle fibers derived from mouse embryos and neonates are also able to synthesize substantial percentages of their AChE as the A12 form when grown in vitro. This synthesis is modulated by a process associated with spontaneous muscle contractile activity since both total enzyme levels and the proportion of A12 AChE expressed on the cell surface are decreased when the cells are grown in the sodium channel blocker tetrodotoxin, which blocks muscle contraction. On the other hand, when the cells are treated with veratridine, which opens sodium channels, thereby mimicking one aspect of muscle contraction, their AChE levels are comparable to those of untreated cells. Although smaller in magnitude, these changes are similar to those seen in rat muscle cultures. A novel feature of mouse muscle cultures, not seen in those from rat and chick, is the presence of a secreted enzyme form that sediments in the same position as the cellular A12 form (when separated on sucrose density gradients containing high salt) and is also collagenase sensitive.     

Potential antifilarial activity of fruit extracts of Ficus racemosa Linn. against Setaria cervi in vitro

Effect of alcoholic and aqueous extracts of the fruits of F. racemosa Linn., on the spontaneous movements of both the whole worm and nerve muscle preparation of Setaria cervi and on the survival of microfilariae in vitro was studied. Alcoholic as well as aqueous extracts caused inhibition of spontaneous motility of whole worm and nerve muscle preparation of Setaria cervi characterized by increase in amplitude and tone of contractions. Initial stimulatory effect was not observed with aqueous extract on whole worm preparation, while effect of alcoholic extract on whole worm and nerve muscle preparation was characterized by an increase in amplitude and tone of contractions followed by paralysis. The concentrations required to inhibit the movement of the whole worm and nerve muscle preparation for alcoholic extract of fruits of F. racemosa were 250 and 50 microg/ml, respectively, whereas aqueous extract caused inhibition of the whole worm and nerve muscle preparation at 350 and 150 microg/ml, respectively, suggesting a cuticular barrier. Both alcoholic and aqueous extracts caused death of microfilariae in vitro. LC50 and LC90 were 21 and 35 ng/ml, respectively for alcoholic, which were 27 and 42 ng/ml for aqueous extracts.