Nicotinic acid decarboxylation in tobacco roots

An enzyme system which catalyzes the O₂ dependent release of ¹⁴CO₂ from nicotinic acid-7-¹⁴C is present in tobacco roots. The enzyme is not present in tobacco leaves and stems. The nature of reaction catalyzed and its tissue distribution suggest that this enzyme may be involved in nicotine biosynthesis.     

A study of behavioural habituation to a feeding deterrent in nymphs of Schistocerca gregaria

ABSTRACT. Behavioural habituation† of Schistocerca gregaria Forskål fifth instar larvae to a feeding deterrent, nicotine hydrogen tartrate (NHT), is described. An attempt was made to differentiate between various factors possibly involved in the induction of this behavioural habituation. Sensory stimulation (through maxillary palp), cannulation of NHT into the crop, and its administration by gelatine capsules placed into the oesophagus each resulted in behavioural habituation, but in the latter two cases a sole induction via post-ingestional input is not completely proven. Injection of NHT into the haemolymph did not induce habituation. It is concluded that habituation via sensory stimulation is a central phenomenon.     

Effects of nicotine on rat adrenal gland: crosstalk between oxidative and inflammatory markers,and amelioration by melatonin

Although the risks of smoking are well known, the effects of exposure to nicotine on endocrine functions remain unclear. We investigated the deleterious effects of nicotine on the adrenal gland and the mechanisms of these changes in rats. The role of melatonin in ameliorating pathological changes also was investigated. We used 24 rats divided into four groups of six: group 1, control; group 2, nicotine treated; group 3, nicotine and melatonin treated; group 4, melatonin treated. We used histology; immunohistochemistry of inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF) and tyrosine hydroxylase (TH); measured oxidative and antioxidative markers, malondialdehyde (MDA) and glutathione (GSH); and performed real-time PCR for NF-κB 65, IL1-B and IL6. We also performed histomorphometric analysis. Indentation and lamellar separation of the adrenal capsule, vacuolated degenerated cells and lymphocytic infiltration were observed in group 2. Vacuolated cells and cells with pyknotic nuclei also were detected in the zona reticularis and medulla of the same group. We observed improved shape and cellular lining of the gland in groups 3 and 4. Widespread expression of iNOS, VEGF and TH, increased area percent collagen, decreased GSH (56%) and increased MDA, NF-κB, IL1-B and IL-6 were observed in group 2. All parameters were ameliorated in groups 3 and 4. The effects of nicotine on the adrenal gland can be attributed to oxidative and inflammatory stress; melatonin ameliorates these effects.     

Carcinoma of buccal mucosa in smokeless tobacco users: a preliminary study of the use of cytology for early detection

A type of smokeless tobacco, known as Maras powder, is widely used in lieu of cigarettes in the south-eastern region of Turkey. In the present study, we evaluated cytological smears obtained from the lesion of lower lip mucosa of 80 smokeless tobacco users. There were severe epithelial abnormalities in seven out of the 80 subjects. Punch biopsies from these cases disclosed dysplasia in three cases, carcinoma in situ in two, and carcinoma in the other two cases. There was mild dysplasia in two punch biopsies of the remaining 73 cases. Oral cancer in tobacco powder users appeared to be related to the length of use, as it was observed only in subjects with 15 or more years of exposure.