Biomedical subjects

David A Taylor

Publications and source records attributed to David A Taylor.

15 recordsLinked to original sources

PubMed2006

Cannabidiol reverses MK-801-induced disruption of prepulse inhibition in mice.

Cannabidiol, a nonpsychoactive constituent of the Cannabis sativa plant, has been reported to act as an agonist of the vanilloid 1 channel in the transient receptor potential family (TRPV1) and also to inhibit the hydrolysis and cellular uptake of the endogenous cannabinoid anandamide. Cannabidiol has also been reported to have potential as an antipsychotic. We investigated the effect of cannabidiol on sensorimotor gating deficits in mice induced by the noncompetitive NMDA receptor antagonist, MK-801. Sensorimotor gating is deficient in psychotic disorders such as schizophrenia and may be reliably measured by prepulse inhibition (PPI) of the startle response in rodents and humans. MK-801 (0.3-1 mg/kg i.p.) dose dependently disrupted PPI while cannabidiol (1-15 mg/kg i.p.), when administered with vehicle, had no effect on PPI. Cannabidiol (5 mg/kg i.p.) successfully reversed disruptions in PPI induced by MK-801 (1 mg/kg i.p.), as did the atypical antipsychotic clozapine (4 mg/kg i.p.). Pretreatment with capsazepine (20 mg/kg i.p.) prevented the reversal of MK-801-induced disruption of PPI by cannabidiol, providing preliminary evidence that TRPV1 receptors are involved in the reversal of MK-801-induced sensorimotor gating deficits by cannabidiol.

Analysis of Variance↗

PubMed2005

Can claims, misleading information, and manufacturing issues regarding dietary supplements be improved in the United States?

The safety and effectiveness of over-the-counter (OTC) drugs are assessed through the Food and Drug Administration's (FDA's) OTC drug review. Prescription drugs are approved through the rigorous new drug application (NDA) process. In contrast, dietary supplements are regulated as foods, and the FDA must determine that a dietary supplement ingredient poses a "significant or unreasonable risk of illness or injury" instead of requiring the manufacturer to provide safety data. According to the FDA, there are more than 29,000 different dietary supplements available to consumers today. This momentum has its roots in consumer interest in health and self-care and suggests that Americans are searching for alternatives to conventional foods for physical and mental well being. The Committee on the Framework for Evaluating the Safety of Dietary Supplements was formed under the auspices of the Food and Nutrition Board that produced a report entitled Dietary Supplements: A Framework for Evaluating Safety. Categories of specific information identified for use are 1) human data, 2) animal studies, 3) in vitro experiments, and 4) information on related substances. Several factors were identified to guide the FDA in applying the framework. Two of these factors are expressed as follows: 1) "the appropriate scientific standard to be used to overturn this basic assumption of safety is to demonstrate significant or unreasonable risk, not prove that an ingredient is unsafe"; and 2) "approaches taken by diverse organizations and governmental bodies, both within and outside the United States, which evaluate the safety and at times efficacy of dietary supplement ingredients, vary in their relevance to the protection of the American public from risks associated with consumption of dietary supplement ingredients".

Dietary Supplements↗

PubMed2005

The effect of buprenorphine and benzodiazepines on respiration in the rat.

Methadone and buprenorphine are the two main opioid substitution treatments for heroin dependence currently offered in Australia. A number of publications have implicated buprenorphine as being potentially dangerous in combination with benzodiazepines but no comparison has been made to the relative dangers of benzodiazepines combined with buprenorphine or methadone. The effect of i.v. methadone and buprenorphine on respiration was investigated by evaluating arterial blood pCO2, pO2 and pH, and measuring respiratory rate in rats. Measurements were taken at 0, 15, 30, 60, 120, 180 and 240 min after i.v. administration of methadone or buprenorphine. Effects on respiration were greatest 15 min after i.v. drug administration. The effect of methadone and buprenorphine on respiration was compared with and without diazepam pretreatment (20 mg/kg). Buprenorphine alone exhibited a bell shaped dose response inhibition of respiration; however the plateau of the dose response inhibition on respiration was lost when administered in combination with diazepam. Methadone showed a dose-dependent inhibitory effect on respiration, which was potentiated with diazepam pretreatment. While the effect of diazepam pretreatment was the abolishment of the protective bell shaped dose response effect on respiration, the effect of buprenorphine and diazepam was not greater than methadone and diazepam.

Animals↗

PubMed2005

Sweet deal for cocoa production?

Explore the source record for details and available documents.

Agriculture↗

PubMed2004

The effect of SR 141716 and apomorphine on sensorimotor gating in Swiss mice.

The aim of the present study was to investigate in Swiss mice the acute effects of the CB(1) receptor antagonist N-piperidino-5-(4-chlorphenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (SR 141716) alone and in combination with apomorphine, a D(1)/D(2) receptor agonist, on prepulse inhibition (PPI) of the acoustic startle response, an operational measure of sensorimotor gating. SR 141716 (1 and 3 mg/kg i.p.) had no significant effect on PPI. Apomorphine (3 mg/kg i.p.) significantly disrupted PPI. The PPI of mice injected with SR 141716 (1 mg/kg i.p.) plus apomorphine (3 mg/kg i.p.) was not significantly different to that of vehicle plus apomorphine (3 mg/kg i.p.)-treated mice. However, the higher dose of SR 141716 used (3 mg/kg i.p.) significantly inhibited the disruption of PPI produced by apomorphine. These results suggest that antagonism of CB(1) receptors with SR 141716 has no significant effect on sensorimotor gating in Swiss mice. However, CB(1) receptors appear to be important in the effect of apomorphine on sensorimotor gating, as antagonism of CB(1) receptors with SR 141716 inhibits apomorphine-induced disruptions.

Animals↗

PubMed2004