veratrine and Vomiting

We subcutaneously injected 0.5 mg/kg veratrine into the musk shrew (Suncus murinus), observed the presence or absence, latency, and the incidence of vomiting in each animal for 90 min, and selected animals that frequently vomited (FV group) and those that did not vomit (NV group). Subsequently, animal brains were removed, and the induction of c-fos protein (Fos) was immunohistochemically examined to evaluate neuronal activity in the medulla oblongata. The distribution of Fos-positive neurons in the medulla oblongata was similar between FV and NV groups, with numerous neurons along the entire length of the nucleus of the solitary tract and in the ventrolateral reticular formation. Both veratrine-injected groups showed higher numbers of positive neurons than the saline administered group. However, while the FV group showed a high concentration of positive neurons in the dorsal-dorsomedial reticular formation of the nucleus ambiguus in the rostral medulla, the NV group showed few positive neurons in this area. Fos activity in neurons in this area appeared to be higher in animals with a higher incidence of vomiting.

Topics: Animals; Female; Immunohistochemistry; Injections, Subcutaneous; Male; Medulla Oblongata; Neurons; Proto-Oncogene Proteins c-fos; Shrews; Veratrine; Vomiting

The emetic (vomiting) reflex in a crocodilian, Crocodylus porosus, was characterised for the first time using the plant alkaloid veratrine (5 mg kg(-)(1) i.v. or i.p.) as an emetic stimulus. The latency to the onset of vomiting was 8.0+/-0.9 min (mean +/- s.e.m., N=5 animals). Vomiting was preceded by a clearly defined set of prodromal behaviours including, in temporal sequence, rhythmic contraction of the pharynx, sneezing and jaw snapping. Expulsion of vomitus was not particularly forceful and was accompanied by lateral shaking of the head. Physiological studies revealed that vomiting was accompanied by oscillatory (9.1+/-0.7 oscillations over 29.7+/-3. 6 s, N=9 episodes in three animals) increases in intraperitoneal pressure (7.0+/-0.9 kPa, cf. 0.7+/-0.1 kPa during respiration). The significance of these results is discussed in the context of the role(s) of vomiting as a protective reflex and as a mechanism for removal of indigestible food residues (e.g. fur, claws) from the gut.

Topics: Abdomen; Alligators and Crocodiles; Animals; Behavior, Animal; Electrocardiography; Heart Rate; Pressure; Reflex; Veratrine; Vomiting

Topics: Aging; Animals; Breeding; Female; Male; Selection, Genetic; Sex Characteristics; Shrews; Veratrine; Vomiting

In order to elucidate possible male/female differences in emesis, the effects of various emetogenic drugs (cisplatin, copper sulfate, veratrine, nicotine, serotonin) and motion stimulus were compared between male and female Suncus murinus. Cisplatin (IP), nicotine (SC), veratrine (SC) and copper sulfate (PO) induced dose-dependent emesis in either sex, and there was no apparent difference in estimated ED50 values. However, male animals tended to be more susceptible to serotonin-induced emesis. The ID50 values for tropisetron, a 5-HT3 receptor antagonist, to block serotonin-induced emesis were also similar between male and female animals. However, tropisetron was less effective against cisplatin-induced emesis in females. Therefore, cisplatin may release more serotonin to induce emesis in females. Reciprocal shaking (horizontal oscillation 40 mm, frequency 0.5 to 2.0 Hz, duration 5 min) induced more frequent emesis in male animals, and the latency to the first vomit was shorter in males than in females. These results suggest that there is substantial sex-dependent difference in the emetic responses and male animals are in general more susceptible. These results are discussed in the light of similar studies in man.

Topics: Animals; Antiemetics; Cisplatin; Copper Sulfate; Female; Indoles; Male; Motion Sickness; Nicotine; Receptors, Serotonin; Receptors, Serotonin, 5-HT3; Serotonin; Serotonin Antagonists; Sex Factors; Shrews; Tropisetron; Veratrine; Vomiting

We have shown previously that Suncus murinus, a species of the insectivore, can vomit in response to various emetogenic stimuli. In the present study we investigated whether or not Sorex unguiculatus, which belongs to different subfamily (Soricinae) of insectivore, vomits in response to emetogenic drugs. Subcutaneous injection of veratrine and oral administration of copper sulfate caused emesis in the animal. Histological study showed that bilateral structure of the area postrema was not important for the emetic reflex. Therefore, the capability of emesis may be common to the family of soricidae of the insectivore, and the Sorex unguiculatus is the smallest known mammal which can vomit.

Topics: Animals; Copper; Copper Sulfate; Eulipotyphla; Mesencephalon; Reflex; Veratrine; Vomiting

Topics: Aconitum; Alkaloids; Animals; Blood Pressure; Cats; Dogs; Electric Stimulation; Neurons, Afferent; Reflex; Vagus Nerve; Veratrine; Vomiting

Topics: Aconitine; Alkaloids; Animals; Dogs; Emetics; Ganglia; Pharmacology; Pons; Research; Vagus Nerve; Veratrine; Vomiting