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Papers by Lamini Ouedraogo
Journal of Insect Physiology, 2018
Action potentials from individual cells were recorded from antennae (funiculi) of living tsetse f... more Action potentials from individual cells were recorded from antennae (funiculi) of living tsetse flies, Glossina p. palpalis and Glossina f. fuscipes using a "surface-contact" recording technique. Stimuli were vapours of 1-octen-3ol, acetone and 3-methylphenol. Of the 101 and 128 olfactory cells tested for their sensitivity to odour stimuli in G. p. palpalis and G. f. fuscipes, respectively, the majority (83 and 77%) were activated by more than one chemical. The numbers of these "generalist" cells were 20 and 15% higher in females than in males. Response intensity increased with increasing odour dose. Temporal patterns of excitation were phasic-tonic and showed cells with relatively rapid cessation of spike activity after the end of stimulation and cells which continued firing for several seconds or even minutes after stimulation. Inhibition by odours only occurred in a minority of cells and was dose-dependent. For each of the three substances the excitatory response was significantly higher in G. f. fuscipes than in G. p. palpalis, whereas no significant differences between inhibitory responses were found. In G. f. fuscipes each stimulus evoked equal excitatory responses. In G. p. palpalis, however, acetone induced significantly higher responses than 1-octen-3-ol and 3-methylphenol. Response intensities to each of the three chemicals did not differ between male and female G. p. palpalis, whereas in G. f. fuscipes 1-octen-3-ol evoked significantly higher responses in males. Possible mechanisms of receptor cell odour coding and behavioural effects of the various cell type activities are discussed.
African Journal of Traditional, Complementary and Alternative Medicines, 2005
The present study was designed to investigate the blocking of calcium by the hydroalcoholic extra... more The present study was designed to investigate the blocking of calcium by the hydroalcoholic extract of Tapinanthus dodoneifolius (Tapidod), "in vitro", on rat trachea. To evaluate this effect, the contractile activity of tracheal chains from Wistar Kyoto rats was isometrically recorded. On the isolated tracheal rings the extract produced the following effects: (a) a reduction of the contraction obtained by BaCl 2 , (b) a bronchorelaxing action, on strips precontracted by KCl, which was not influenced by TEA (3x10-3 M), (c) a concentrationdependent decrease of the spasm evoked by calcium chloride (CaCl 2) in K-rich Ca-free physiological salt solution + 2+ , before and after intracellular calcium depletion (d), an inhibitory effect on contraction induced by acetylcholine in Ca-free Krebs-Heinseleit solution supplemented with 2+ EDTA (5x10-4 M). It is concluded that: 1. The activation of the potassium channels does not play a significant role in the relaxant effect of Tapidod. 2. The antispasmodic property of Tapidod seems to be mediated by the blockade of intracellular Ca 2+ release. 3. Most likely an inhibition of the intracellular Ca 2+-regulating proteins is involved.
Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie, 1997
Isolated ventricles of developing chick embryo heart, paced at 1 Hz, were used to assess the posi... more Isolated ventricles of developing chick embryo heart, paced at 1 Hz, were used to assess the positive inotropic responses to isoprenaline and noradrenaline in order to characterize the adrenergic receptors involved in these effects. In 7 day-old-chick embryo heart ventricle, isoprenaline and noradrenaline exhibited similar potencies and efficacies. Moreover, propranolol (1 microM) inhibited the positive inotropic effect of isoprenaline and noradrenaline, while pentholamine (3 microM) failed to affect the latter response; in addition, phenylephrine (1 microM-1 mM) had no positive inotropic effect. It was therefore concluded that isoprenaline and noradrenaline induce their effect via stimulation of beta-adrenergic receptors. The efficacy of isoprenaline and noradrenaline and the potency of isoprenaline increased from the 7th to 10th day while the potency of noradrenaline decreased. The decrease in noradrenaline potency with age was attributed to its uptake, while the increase in isopr...
Fundamental & Clinical Pharmacology, 1998
Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors ... more Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors in dopamine induced inotropism in myocardium. We therefore used electrically stimulated (1 Hz) isolated 7-day-old chick embryo heart ventricles, thought to be. devoid of functional sympathetic nerves, to re-investigate post-synaptic receptors involvement and particularly that of dopaminergic receptors in the positive inotropic effect of dopamine. The results showed that noradrenaline, isoprenaline and dopamine produced a positive inotropic effect with a similar efficacy and with an order of potency as follows: Isoprenaline = Noradrenaline > Dopamine. Tyramine induced no significant modification of the "initial tension" indicating that functional sympathetic innervation and/or releasable endogenous catecholamines were not demonstrable in the 7-day-old chick embryo heart ventricle. Propranolol (1 pM) competitively antagonized the positive inotropic response to isoprenaline, noradrenaline and dopamine, meanwhile phentolamine (3 pM) failed to significantly modify the effects of both noradrenaline and dopamine, indicating that these catecholamines induced their positive inotropic effects via stimulation of Fadrenoceptors; involvement of a-adrenergic receptors stimulation was not demonstrable in these effects. Moreover, haloperidol (2 pM) antagonized the positive inotropic response to dopamine but had not any significant effect on the response to isoprenaline. The combined application of both propranolol and haloperidol antagonized the positive inotropic response to dopamine to a greater extent than when these two antagonists were given alone. Consequently, post-synaptic dopaminergic receptors were also involved in the positive inotropic effect of dopamine. Furthermore. in preparations in which sodium channels were inactivated by high potassium physiological salt solution, high concentrations of dopamine (0.1 mM to 1 mM) induced a slow developing electrical and positive inotropic responses which were also inhibited by propranolol and haloperidol. but not by phentolamine. These 1at~e.r results indicated that like Padrenergic stimulation, the slow inward calcium current activated by stimulation of adenylate cyclase, was at least in part involved in the positive inotropic response to dopamine. In conclusion, dopamine induced its positive inotropism via stimulation of post-synaptic &adrenergic and dopaminergic receptors. The contribution of dopaminergic receptors in this positive inotropic effect might be. of the DA-2 receptors since haloperidol used had been reported to be more DA-2 than DA-I antagonist. These DA-2 receptors subtypes would mediate activation of adenylate cyclase. 0 1998 Elsevier. Paris. chick embryo heart ventricle / positive inotropic response / a; and Badremrgic receptors / dopaminergic receptors I post/synaptic reCept0I-S
Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie, 1997
Comptes Rendus De L Academie Des Sciences Serie Iii-sciences De La Vie-life Sciences, 1997
Fundamental & Clinical Pharmacology, 1998
Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors ... more Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors in dopamine induced inotropism in myocardium. We therefore used electrically stimulated (1 Hz) isolated 7-day-old chick embryo heart ventricles, thought to be. devoid of functional sympathetic nerves, to re-investigate post-synaptic receptors involvement and particularly that of dopaminergic receptors in the positive inotropic effect of dopamine. The results showed that noradrenaline, isoprenaline and dopamine produced a positive inotropic effect with a similar efficacy and with an order of potency as follows: Isoprenaline = Noradrenaline > Dopamine. Tyramine induced no significant modification of the "initial tension" indicating that functional sympathetic innervation and/or releasable endogenous catecholamines were not demonstrable in the 7-day-old chick embryo heart ventricle. Propranolol (1 pM) competitively antagonized the positive inotropic response to isoprenaline, noradrenaline and dopamine, meanwhile phentolamine (3 pM) failed to significantly modify the effects of both noradrenaline and dopamine, indicating that these catecholamines induced their positive inotropic effects via stimulation of Fadrenoceptors; involvement of a-adrenergic receptors stimulation was not demonstrable in these effects. Moreover, haloperidol (2 pM) antagonized the positive inotropic response to dopamine but had not any significant effect on the response to isoprenaline. The combined application of both propranolol and haloperidol antagonized the positive inotropic response to dopamine to a greater extent than when these two antagonists were given alone. Consequently, post-synaptic dopaminergic receptors were also involved in the positive inotropic effect of dopamine. Furthermore. in preparations in which sodium channels were inactivated by high potassium physiological salt solution, high concentrations of dopamine (0.1 mM to 1 mM) induced a slow developing electrical and positive inotropic responses which were also inhibited by propranolol and haloperidol. but not by phentolamine. These 1at~e.r results indicated that like Padrenergic stimulation, the slow inward calcium current activated by stimulation of adenylate cyclase, was at least in part involved in the positive inotropic response to dopamine. In conclusion, dopamine induced its positive inotropism via stimulation of post-synaptic &adrenergic and dopaminergic receptors. The contribution of dopaminergic receptors in this positive inotropic effect might be. of the DA-2 receptors since haloperidol used had been reported to be more DA-2 than DA-I antagonist. These DA-2 receptors subtypes would mediate activation of adenylate cyclase. 0 1998 Elsevier. Paris. chick embryo heart ventricle / positive inotropic response / a; and Badremrgic receptors / dopaminergic receptors I post/synaptic reCept0I-S
Journal of Insect Physiology, 2018
Action potentials from individual cells were recorded from antennae (funiculi) of living tsetse f... more Action potentials from individual cells were recorded from antennae (funiculi) of living tsetse flies, Glossina p. palpalis and Glossina f. fuscipes using a "surface-contact" recording technique. Stimuli were vapours of 1-octen-3ol, acetone and 3-methylphenol. Of the 101 and 128 olfactory cells tested for their sensitivity to odour stimuli in G. p. palpalis and G. f. fuscipes, respectively, the majority (83 and 77%) were activated by more than one chemical. The numbers of these "generalist" cells were 20 and 15% higher in females than in males. Response intensity increased with increasing odour dose. Temporal patterns of excitation were phasic-tonic and showed cells with relatively rapid cessation of spike activity after the end of stimulation and cells which continued firing for several seconds or even minutes after stimulation. Inhibition by odours only occurred in a minority of cells and was dose-dependent. For each of the three substances the excitatory response was significantly higher in G. f. fuscipes than in G. p. palpalis, whereas no significant differences between inhibitory responses were found. In G. f. fuscipes each stimulus evoked equal excitatory responses. In G. p. palpalis, however, acetone induced significantly higher responses than 1-octen-3-ol and 3-methylphenol. Response intensities to each of the three chemicals did not differ between male and female G. p. palpalis, whereas in G. f. fuscipes 1-octen-3-ol evoked significantly higher responses in males. Possible mechanisms of receptor cell odour coding and behavioural effects of the various cell type activities are discussed.
African Journal of Traditional, Complementary and Alternative Medicines, 2005
The present study was designed to investigate the blocking of calcium by the hydroalcoholic extra... more The present study was designed to investigate the blocking of calcium by the hydroalcoholic extract of Tapinanthus dodoneifolius (Tapidod), "in vitro", on rat trachea. To evaluate this effect, the contractile activity of tracheal chains from Wistar Kyoto rats was isometrically recorded. On the isolated tracheal rings the extract produced the following effects: (a) a reduction of the contraction obtained by BaCl 2 , (b) a bronchorelaxing action, on strips precontracted by KCl, which was not influenced by TEA (3x10-3 M), (c) a concentrationdependent decrease of the spasm evoked by calcium chloride (CaCl 2) in K-rich Ca-free physiological salt solution + 2+ , before and after intracellular calcium depletion (d), an inhibitory effect on contraction induced by acetylcholine in Ca-free Krebs-Heinseleit solution supplemented with 2+ EDTA (5x10-4 M). It is concluded that: 1. The activation of the potassium channels does not play a significant role in the relaxant effect of Tapidod. 2. The antispasmodic property of Tapidod seems to be mediated by the blockade of intracellular Ca 2+ release. 3. Most likely an inhibition of the intracellular Ca 2+-regulating proteins is involved.
Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie, 1997
Isolated ventricles of developing chick embryo heart, paced at 1 Hz, were used to assess the posi... more Isolated ventricles of developing chick embryo heart, paced at 1 Hz, were used to assess the positive inotropic responses to isoprenaline and noradrenaline in order to characterize the adrenergic receptors involved in these effects. In 7 day-old-chick embryo heart ventricle, isoprenaline and noradrenaline exhibited similar potencies and efficacies. Moreover, propranolol (1 microM) inhibited the positive inotropic effect of isoprenaline and noradrenaline, while pentholamine (3 microM) failed to affect the latter response; in addition, phenylephrine (1 microM-1 mM) had no positive inotropic effect. It was therefore concluded that isoprenaline and noradrenaline induce their effect via stimulation of beta-adrenergic receptors. The efficacy of isoprenaline and noradrenaline and the potency of isoprenaline increased from the 7th to 10th day while the potency of noradrenaline decreased. The decrease in noradrenaline potency with age was attributed to its uptake, while the increase in isopr...
Fundamental & Clinical Pharmacology, 1998
Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors ... more Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors in dopamine induced inotropism in myocardium. We therefore used electrically stimulated (1 Hz) isolated 7-day-old chick embryo heart ventricles, thought to be. devoid of functional sympathetic nerves, to re-investigate post-synaptic receptors involvement and particularly that of dopaminergic receptors in the positive inotropic effect of dopamine. The results showed that noradrenaline, isoprenaline and dopamine produced a positive inotropic effect with a similar efficacy and with an order of potency as follows: Isoprenaline = Noradrenaline > Dopamine. Tyramine induced no significant modification of the "initial tension" indicating that functional sympathetic innervation and/or releasable endogenous catecholamines were not demonstrable in the 7-day-old chick embryo heart ventricle. Propranolol (1 pM) competitively antagonized the positive inotropic response to isoprenaline, noradrenaline and dopamine, meanwhile phentolamine (3 pM) failed to significantly modify the effects of both noradrenaline and dopamine, indicating that these catecholamines induced their positive inotropic effects via stimulation of Fadrenoceptors; involvement of a-adrenergic receptors stimulation was not demonstrable in these effects. Moreover, haloperidol (2 pM) antagonized the positive inotropic response to dopamine but had not any significant effect on the response to isoprenaline. The combined application of both propranolol and haloperidol antagonized the positive inotropic response to dopamine to a greater extent than when these two antagonists were given alone. Consequently, post-synaptic dopaminergic receptors were also involved in the positive inotropic effect of dopamine. Furthermore. in preparations in which sodium channels were inactivated by high potassium physiological salt solution, high concentrations of dopamine (0.1 mM to 1 mM) induced a slow developing electrical and positive inotropic responses which were also inhibited by propranolol and haloperidol. but not by phentolamine. These 1at~e.r results indicated that like Padrenergic stimulation, the slow inward calcium current activated by stimulation of adenylate cyclase, was at least in part involved in the positive inotropic response to dopamine. In conclusion, dopamine induced its positive inotropism via stimulation of post-synaptic &adrenergic and dopaminergic receptors. The contribution of dopaminergic receptors in this positive inotropic effect might be. of the DA-2 receptors since haloperidol used had been reported to be more DA-2 than DA-I antagonist. These DA-2 receptors subtypes would mediate activation of adenylate cyclase. 0 1998 Elsevier. Paris. chick embryo heart ventricle / positive inotropic response / a; and Badremrgic receptors / dopaminergic receptors I post/synaptic reCept0I-S
Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie, 1997
Comptes Rendus De L Academie Des Sciences Serie Iii-sciences De La Vie-life Sciences, 1997
Fundamental & Clinical Pharmacology, 1998
Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors ... more Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors in dopamine induced inotropism in myocardium. We therefore used electrically stimulated (1 Hz) isolated 7-day-old chick embryo heart ventricles, thought to be. devoid of functional sympathetic nerves, to re-investigate post-synaptic receptors involvement and particularly that of dopaminergic receptors in the positive inotropic effect of dopamine. The results showed that noradrenaline, isoprenaline and dopamine produced a positive inotropic effect with a similar efficacy and with an order of potency as follows: Isoprenaline = Noradrenaline > Dopamine. Tyramine induced no significant modification of the "initial tension" indicating that functional sympathetic innervation and/or releasable endogenous catecholamines were not demonstrable in the 7-day-old chick embryo heart ventricle. Propranolol (1 pM) competitively antagonized the positive inotropic response to isoprenaline, noradrenaline and dopamine, meanwhile phentolamine (3 pM) failed to significantly modify the effects of both noradrenaline and dopamine, indicating that these catecholamines induced their positive inotropic effects via stimulation of Fadrenoceptors; involvement of a-adrenergic receptors stimulation was not demonstrable in these effects. Moreover, haloperidol (2 pM) antagonized the positive inotropic response to dopamine but had not any significant effect on the response to isoprenaline. The combined application of both propranolol and haloperidol antagonized the positive inotropic response to dopamine to a greater extent than when these two antagonists were given alone. Consequently, post-synaptic dopaminergic receptors were also involved in the positive inotropic effect of dopamine. Furthermore. in preparations in which sodium channels were inactivated by high potassium physiological salt solution, high concentrations of dopamine (0.1 mM to 1 mM) induced a slow developing electrical and positive inotropic responses which were also inhibited by propranolol and haloperidol. but not by phentolamine. These 1at~e.r results indicated that like Padrenergic stimulation, the slow inward calcium current activated by stimulation of adenylate cyclase, was at least in part involved in the positive inotropic response to dopamine. In conclusion, dopamine induced its positive inotropism via stimulation of post-synaptic &adrenergic and dopaminergic receptors. The contribution of dopaminergic receptors in this positive inotropic effect might be. of the DA-2 receptors since haloperidol used had been reported to be more DA-2 than DA-I antagonist. These DA-2 receptors subtypes would mediate activation of adenylate cyclase. 0 1998 Elsevier. Paris. chick embryo heart ventricle / positive inotropic response / a; and Badremrgic receptors / dopaminergic receptors I post/synaptic reCept0I-S