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Biomedical subjects

D Jourdan

Publications and source records attributed to D Jourdan.

12 recordsLinked to original sources
PubMed1997

Differential influence of two serotonin 5-HT3 receptor antagonists on spinal serotonin-induced analgesia in rats.

We tested the antinociceptive effect of intrathecal (i.t.) administration of 5-HT3 and the 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide (mCPBG), in rats submitted to a mechanical noxious stimulus and the influence of the 5-HT3 receptor selective antagonists, tropisetron and granisetron. Both 5-HT and mCPBG (0.01, 0.1, 1, 10, 20 micrograms/rat) produced a significant dose-dependent antinociception. The lowest active doses were 0.1 and 1 microgram for 5-HT and mCPBG, respectively. The effect, observed with 20 micrograms, was significantly lower with mCPBG (+33 +/- 6%) than with 5-HT (+63 +/- 7%). For 5-HT-induced antinociception, the minimal inhibitory doses were 0.001 micrograms/rat for tropisetron and 10 micrograms/rat for granisetron. In contrast, the same doses of the two antagonists (from 0.1 microgram/rat) similarly inhibited the effect of mCPBG. This study provides evidence that contrary to tropisetron, doses of granisetron able to inhibit the effect of a 5-HT3 receptor agonist failed to reduce that of 5-HT. This demonstrates a heterogeneity between 5-HT3 receptor antagonists and questions the true involvement of these receptors in spinal 5-HT-induced antinociception.

Animals↗
PubMed1997

A new automated method of pain scoring in the formalin test in rats.

The formalin test is a valuable tool widely used in animal pain studies. We offer a new automated technique based on continuous recording of movements of animals injected in a hindpaw with formalin (5%). This method, based on image processing, allows the discrimination of specific pain-induced behaviors and general motor activity. The comparison of the pain scores evaluated by manual and automated methods showed the same biphasic response. This new process was validated by using compounds known to alter pain responses to formalin: morphine and a non-steroidal anti-inflammatory drug (ketoprofen). Morphine dose-dependently usually affects the two phases of formalin response with ED50 of 2.0 +/- 0.5 and 1.5 +/- 0.5 mg/kg s.c. for the first and the second phase, respectively. The injection of ketoprofen significantly decreased pain scores of the second phase but not those of the first phase. The specificity of the method was studied by determining the effect of diazepam. This sedative compound induced a decrease in pain scores as well as a decrease in motor activity parameters. These data show that this automated technique can be considered as a relevant, sensitive and specific tool which allows the easier use of the formalin test especially for the screening of analgesic drugs.

Analgesics, Opioid↗
PubMed1997

Audible and ultrasonic vocalization elicited by a nociceptive stimulus in rat: relationship with respiration.

Brief electrical pulses applied to a rat's tail elicit complex vocal responses including audible ("peeps," "chatters") and ultrasonic components. These responses, particularly the two first peeps which have been shown to be triggered by A delta- and C-fibers, could provide a useful tool in pain studies. In the present study, we aimed to optimize this test by investigating the influence of respiration on the vocal responses. The following results were obtained: 1) As expected, the vocalization periods were concomitant with expiration; 2) The phase of the respiratory cycle at the onset of stimulation did not modify the mean intensities of the peeps; 3) The lung volume at the onset of stimulation significantly influenced the intensity and duration of the first peep and the latency of the second peep. Taking account of respiratory parameters in pain tests based on a quantified analysis of vocal responses could improve their sensibility by reducing variability and their specificity by detecting confounding factors such as effects of drugs on respiratory centres or on motor function.

Animals↗
PubMed1995

Involvement of bulbospinal pathways in the antinociceptive effect of clomipramine in the rat.

The involvement of bulbospinal pathways in the antinociceptive effect of clomipramine in experimental pain was studied. The antinociceptive effect of the antidepressant (0.5 mg/kg), intravenously injected, was evaluated after a unilateral lesion of the dorsolateral funiculus. The results showed that this effect was suppressed only in the hindpaw ipsilateral to the dorsolateral funiculus lesion, and suggest that the antinociceptive effect of antidepressants needs intact descending inhibitory bulbospinal pathways.

Analgesics↗
PubMed1995

Audible and ultrasonic vocalization elicited by single electrical nociceptive stimuli to the tail in the rat.

We describe audible and ultrasonic vocalization elicited in rats by a short electrical pulse applied to the tail. Three types of vocal emissions were recorded: (1) 'peep', characterized by a repartition of energy over a wide range (0-50 kHz) of frequencies without any clear structure; (2) 'chatters', characterized by an audible (frequencies in hearing range of humans) fundamental frequency (2.47 +/- 0.03 kHz) and harmonics; and (3) 'ultrasonic emissions', characterized by a succession of slightly modulated pulses with frequencies in the 20-35 kHz range. Peeps and chatters were never recorded before the application of the stimuli. Several different vocalization patterns were described in terms of these types of responses. Just after the stimulation, all the animals emitted a 1st peep, which was generally (61%) followed by a 2nd one. They appeared with reproducible latencies, durations and envelopes. The envelopes of the audible (peeps and chatters) responses were intensity-dependent. Experimental data (moving the stimulation site, lidocaine injection) indicated that the 1st and 2nd peeps were triggered by two different groups of peripheral fibres with mean conduction velocities of 7.3 +/- 0.8 and 0.7 +/- 0.1 m/sec, respectively. This suggested an involvement of A delta and C fibres. Morphine showed a naloxone-reversible and dose-dependent antinociceptive effect by decreasing the 1st and 2nd peep envelopes. It is concluded that a short stimulus applied to the tail triggers a complex behavioural repertoire. It is proposed that this model will be a useful tool for physiological and pharmacological studies of nociception.

Anesthetics, Local↗
PubMed1994

[Drugs for relief of pain].

Currently, the pharmacology of analgesics can be sum up to three main compounds: morphine, paracetamol and aspirin. The use of antidepressants and anticonvulsants will also be mentioned. Morphine remains the reference compound among centrally acting analgesics both for acute and chronic pain. Its mechanism of action is relatively well known as well as the role of opiate receptors. Paracetamol is largely used as analgesic for relief of slight to moderate pain. Its mechanism of action still remains unclear. Usually the tolerability of this compound is considered as being excellent. However overdosage can induce severe and possible lethal liver necrosis. Aspirin is also a very old and a largely used compound. Its inhibiting effect on cyclooxygenase acts mainly peripherally but it could also act centrally. According to the current knowledge of its mechanism of action, it seems that the main pharmacological properties as well as adverse events of aspirin are all related to its enzyme inhibiting effect. Slight to moderate pain, related or not to inflammatory disease responds well to aspirin and other NSAIDs.

Acetaminophen↗
PubMed1993

Vocalization elicited by activation of A delta- and C-fibres in the rat.

Complex vocal responses in both the audible and ultrasonic frequency ranges were elicited by a single 2 ms electrical pulse applied to the tail. The first two cries exhibited consistent latencies and durations, were intensity-dependent and were triggered by peripheral fibres with conduction velocities of 7.3 +/- 0.8 and 0.7 +/- 0.1 ms-1, respectively. These behavioural responses are reminiscent of first and second pain triggered by A delta- and C-peripheral fibres in humans. They were followed by irregular audible cries with a fundamental frequency of 1.5 kHz and '22 kHz ultrasonic calls'.

Animals↗
PubMed1989

[Galand disk implant and pupillary block].

We have implanted 530 Galand's disc lens in the last 15 months. Stability and self-centering of implant were good when peroperative vitreous pressure was normal and in any case when wound was closed. Pupillary blocks, specific complications of this lens were rare (less than 1%); they can be prevented occurred by simple and adequate protocols.

Adolescent↗
PubMed1988

[Changes in serum lipids and lipoproteins in 3 cases of heterozygous familial hypercholesterolemia treated by LDL apheresis on dextran sulfate-cellulose columns].

Three patients with heterozygote type IIa hyperlipoproteinemia were treated by specific LDL apheresis with a dextran sulfate-cellulose column every two weeks. Each apheresis resulted in a fall in total cholesterolemia of about 50 p. 100 with a parallel fall in apoprotein B. The average drop of 15 p. 100 in HDL-cholesterol appeared to be due to the hemodilution induced at the end of apheresis. After two months, cholesterol and apoprotein B concentrations before removal were 15 p. 100 lower than baseline values. Treatment was well tolerated. These findings appear encouraging for the treatment of heterozygote forms of familial hyperlipoproteinemia resistant to chemotherapy.

Adult↗