Ethopharmacology: a historical perspective

Antihyperalgesic and Antiallodynic Effects of Amarisolide A and Salvia amarissima Ortega in Experimental Fibromyalgia-Type Pain

Salvia amarissima Ortega is an endemic species of Mexico used in folk medicine to alleviate pain and as a nervous tranquilizer. The S. amarissima extract and one of its abundant metabolites, identified and isolated through chromatographic techniques, were investigated to obtain scientific evidence of its potential effects to relieve nociplastic pain such as fibromyalgia. Then, the extract and amarisolide A (3-300 mg/kg, i.p.) were pharmacologically evaluated in reserpine-induced fibromyalgia-type chronic pain and in depressive-like behavior (as a common comorbidity) by using the forced swimming test in rats. The 5-HT_1A serotonin receptor (selective antagonist WAY100635, 1 mg/kg, i.p.) was explored after the prediction of a chemical interaction using in silico analysis to look for a possible mechanism of action of amarisolide A. Both the extract and amarisolide A produced significant and dose-dependent antihyperalgesic and antiallodynic effects in rats, as well as significant antidepressive behavior without sedative effects when the antinociceptive dosages were used. The 5-HT_1A serotonin receptor participation was predicted by the in silico descriptors and was corroborated in the presence of WAY100635. In conclusion, S. amarissima possesses antihyperalgesic, antiallodynic, and anti-depressive activities, partially due to the presence of amarisolide A, which involves the 5-HT_1A serotonin receptor. This pharmacological evidence suggests that S. amarissima and amarisolide A are both potential alternatives to relieve pain-like fibromyalgia.

Neo-clerodane diterpenic influence in the antinociceptive and anti-inflammatory properties of Salvia circinnata Cav

ETHNOPHARMACOLOGICAL RELEVANCE

Mexico is considered an ancestral center of diversity of Salvia species, however many of them lack scientific information. Salvia circinnata Cav. (syn. Salvia amarissima Ortega) is an endemic species used in traditional medicine to treat disorders attributed to a cold state like anxiety in the central nervous system, as well as gastrointestinal ailments and pain relief.

AIM OF THE STUDY

To give preclinical evidence about the pharmacological properties of this species by investigating its antinociceptive and anti-inflammatory effects, the chemical nature of at least one metabolite, and a possible mechanism of action and adverse effects, using different experimental models of pain.

MATERIAL AND METHODS

Different crude extracts of Salvia circinnata Cav. aerial parts were prepared using increasing polarity and evaluated in the formalin test in mice. This screening allowed to select and evaluate an ethyl acetate extract (EtOAc), as the most bioactive extract, and a metabolite. Antinociceptive and anti-inflammatory activities were confirmed using the plantar test and carrageenan-induced edema. The antinociceptive effects of the extracts were compared to that observed with morphine (1 mg/kg), tramadol (20 mg/kg) or indomethacin (20 mg/kg) as reference drugs. Participation of opioids and TRPV1 receptors was investigated, as well as acute toxicity and adverse effects of sedation and gastric damage.

RESULTS

EtOAc (0.1-10 mg/kg) of S. circinnata Cav. showed a dose-dependent and significant antinociceptive activity, associated in part with the presence of a neo-clerodane glycoside amarisolide A (0.01-1 mg/kg), in the neurogenic and inflammatory phases of the formalin test. Central action of both treatments was corroborated in the plantar test, whereas anti-inflammatory effects were confirmed with the extract (1 and 10 mg/kg) and amarisolide A (1 mg/kg) in the carrageenan-induced edema test. An opioid mechanism in both treatments, and the TRPV1 receptor modulation in the extract were involved. No acute toxicity and adverse effects were noticed with the extract and pure compound in comparison to the reference drugs.

CONCLUSION

These results provide preclinical evidence of the ethnopharmacological antinociceptive S. circinnata Cav. properties, in which the neo-clerodane diterpene glycoside amarisolide A was partially responsible involving the participation of the opioid receptors, while TRPV1 receptor modulation was implicated in the anti-inflammatory activity may be because of the presence of other constituents. This information supports the use of this species in folk medicine for pain therapy.

Ethological concepts enhance the translational value of animal models

The translational value of animal models is an issue of ongoing discussion. We argue that 'Refinement' of animal experiments is needed and this can be achieved by exploiting an ethological approach when setting up and conducting experiments. Ethology aims to assess the functional meaning of behavioral changes, due to experimental manipulation or treatment, in animal models. Although the use of ethological concepts is particularly important for studies involving the measurement of animal behavior (as is the case for most studies on neuro-psychiatric conditions), it will also substantially benefit other disciplines, such as those investigating the immune system or inflammatory response. Using an ethological approach also involves using more optimal testing conditions are employed that have a biological relevance to the animal. Moreover, using a more biological relevant analysis of the data will help to clarify the functional meaning of the modeled readout (e.g. whether it is psychopathological or adaptive in nature). We advocate for instance that more behavioral studies should use animals in group-housed conditions, including the recording of their ultrasonic vocalizations, because (1) social behavior is an essential feature of animal models for human 'social' psychopathologies, such as autism and schizophrenia, and (2) social conditions are indispensable conditions for appropriate behavioral studies in social species, such as the rat. Only when taking these elements into account, the validity of animal experiments and, thus, the translation value of animal models can be enhanced.

A rat-like robot for interacting with real rats

We developed a novel small rat-like robot calledWasedaRat No.4(WR-4) to interact with real rats. WR-4 can perform both rearing (rising up on its hind limbs) and rotating (body bending during movement) actions faster than live mature rats. After robot–rat interaction involving rearing and body grooming (body cuddling and head curling) actions of WR-4, real rats showed more activity and greater interest in the robot. Similar results evident from rat–rat interaction suggest that a rat-like robot is able to interact with rats in the same way as real rats. Furthermore, lower variances between the rat subjects in robot–rat interaction reveals that a rat-like robot can more effectively impact rat's behavior in a controllable, predictable way.

Psychopharmacology's debt to experimental psychology

The role of experimental psychology in the development of psychopharmacology has largely been ignored in recent historical accounts. In this article the authors attempt to redress that gap by outlining work in early experimental psychology that contributed significantly to the field. While psychiatrists focused on the therapeutic nature of drugs or their mimicry of psychopathology, experimental psychologists used psychoactive drugs as tools to study individual differences in normal behavior as well as to develop methodologies using behavior to study mechanisms of drug action. Experimental work by Kraepelin, Rivers, and Hollingworth was particularly important in establishing drug-screening protocols still used today. Research on nitrous oxide and on the effects of drug combinations is discussed to illustrate the importance of experimental psychology to psychopharmacology.

A comparative neuroethological study of limbic seizures induced by Parawixia bistriata venom and kainic acid injections in rats

A number of neurotoxins derived from arthropod venoms are known to show highly selective effects on nervous tissue. These neurotoxins have been proved to be extremely useful tools to investigate either convulsive or anticonvulsive mechanisms in the nervous system. In the present work, intracerebroventricular injection of the crude venom from the spider Parawixia bistriata (Araneae, Araneidae) in rats induced convulsive limbic seizures (head and forelimb myoclonus, as well as rearing and falling). Neuroethological analysis showed that the limbic seizures induced by the venom were different from those induced by kainic acid. Intravenous injection of the same venom did not induce seizures, but the neuroethological analysis showed an intensification of grooming behavior similar to a displaced activity. In conclusion, our experiments point that crude venom of P. bistriata may contain convulsant neurotoxins probably acting in limbic system structures. The mechanism of action of these neurotoxins may be different from simple activation of glutamatergic kainate receptors, as evidenced by a comparative neuroethological analysis of seizures induced by either venom or kainic acid.

Combined effects of Gepirone and (+)WAY 100135 on territorial aggression in mice

The purpose of this investigation was to elucidate the involvement of the serotonergic 5-HT1A system in the control of aggression. The paradigm was the response of a resident mouse to an intruder into its territory. Three experiments were performed to assess the action of various doses of Gepirone (a partial agonist) and (+)WAY 100135 (a putative antagonist), separately and in combination, on aggression and on rectal body temperature. The most consistent action of Gepirone was an increase in the latency to attack. After initiation of fighting, rates of attack, chase, and tail rattling were reduced in a dose-dependent manner by i.p. administration of 2.5, 5, and 10 mg/kg of Gepirone. There was no evidence of sedation or motor impairment, but autogrooming was decreased. When doses of 2.5, 5, and 10 mg/kg of (+)WAY 100135 (WAY) were given, no effects whatsoever on aggressive or other behaviors were observed. In a third experiment, a two-factor design was followed in which injection of WAY (0, 2.5, and 5 mg/kg) was followed 15 min later by injection of Gepirone (0, 2.5, 5, and 10 mg/kg). WAY decreased attack latency, increased attack rate, and attenuated the marked dose-dependent aggression reducing properties of Gepirone. The test procedure resulted in "stress hyperthermia," which was reduced by Gepirone and increased by WAY. In both behavioral and temperature measures, the larger dose of WAY proved to be less effective than the smaller one. The results support the involvement of the 5-HT1A system in the modulation of some forms of aggression.

Scientific Methodology in temporomandibular disorders. Part II: ethology

The historical background of ethology and the paradigm of clinical treatment as scientific experiment, rather than practice of the art of dentistry are discussed. Ethology is defined and explained relative to the study of temporomandibular disorders (TMDs) using instrumentation, measurement and retrospective clinical studies of successfully treated cases as meaningful research for improvement of future treatment.