5-hydroxytryptamine (5-HT) has become one of the most investigated and complex biogenic amines. The main receptors and their subtypes e.g. 5-HTI (5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E and 5-HT1F ), 5-HT (5-HT2A, 5-HT2B and 5-HT2C) , 5-HT3 and 5-HT4 have been identified. Additional receptors e.g., 5-HT5, 5-HT6 and subtypes of 5-HT3 have been proposed. Specific drugs which are capable of either selectively stimulating or inhibiting these receptor subtypes are being designed. This has generated great interest in exploring the therapeutic potentials of 5-HT receptor modulators in a variety of disease conditions. Conditions where 5-HT receptor modulators have established their use with distinct efficacy and advantages include migraine, anxiety and cancer therapy-induced vomiting by cytotoxic drugs and radiation. Based on the knowledge of their role in the pathophysiology of diseases, findings of animal experiments or early clinical trials, these agents have shown promise in ameliorating a number of ailments and symptoms. The potential of 5-HT receptor modulators in pain, schizophrenia, depression, parkinsonism, drug abuse, aggression, irritable bowel syndrome, carcinoid syndrome, dyspepsia, non-cardiac chest pain, gastroesophageal reflux disease, diabetic gastroparesis, hypertension, peripheral vascular diseases and glaucoma have been discussed in this article.

Hepatic microsomal system, similar to ethanol, for the oxidation of Ethylene Glycol (EG) at the initial step has been found to exist besides the cytosolic route by alcohol dehydrogenase (ADH). Normal rat liver oxidised EG to the extent of 25.7% via microsomes and 74.3% by ADH. The EG pretreated rat liver oxidised EG by 37% and 63% via microsomes and ADH respectively. The Km value for EG oxidation by microsomes and ADH is higher than the reported Km for ethanol under similar conditions. The greater affinity of microsomal and ADH route for ethanol than for EG explains the effective role of ethanol as an antidote in cases of acute EG poisoning.

The efficacy and tolerability of cetirizine, a second generation H1 receptor blocker, was evaluated in perennial allergic rhinitis patients. Fifty-one of them, took part in a double blind randomized study during which they were treated for 4 weeks with either cetirizine 10 mg (n=17) or astemizole 10 mg (n=18) or placebo (n=16) with once daily oral dose. Nine patients were excluded from the trial due to non-compliance or protocol violation. Our study revealed that cetirizine alleviated almost all the symptoms of perennial allergic rhinitis viz., sneezing, rhinorrhoea, nasal obstruction and nasal pruritus. Cetirizine and astemizole did not differ significantly in either efficacy or toleration, though both had efficacy superior to placebo. Cetirizine may be a useful antihistamine in the treatment of perennial allergic rhinitis for its long action, non-sedative property and convenient dosing schedule.

A study was conducted on Wistar male rats to assess the effect of chronic alcohol administration on blood ethanol and acetaldehyde levels and their modification by Liv.52, an Ayurvedic formulation. Following chronic ingestion of 6% alcohol (v/v) through a water feeding bottle for 42 days, the administration of an acute oral dose of 5 ml of 5% alcohol (v/v) resulted in a significant decrease (P < 0.05) in blood ethanol and significant increase (P < 0.05) in acetaldehyde levels respectively at 30 min. Larger doses (i.e., 5 ml of 10% and 15% respectively) failed to demonstrate an effect of accelerated ethanol metabolism because of saturation kinetics. In the second experiment, temporal observations on blood ethanol and acetaldehyde levels were done at 1, 3 and 4 h. Following chronic ingestion of 6% alcohol for 42 days, stimulation of Phase I and suppression of Phase II metabolism was reproduced at all the time points, As compared with placebo, treatment with Liv.52 in the last two weeks reversed the blood ethanol and acetaldehyde levels (P < 0.005) at all the time points and they were comparable to the levels observed on day 1 (basal readings). In the third experiment, chronic exposure to 6% alcohol for 180 days showed further deterioration in ethanol metabolism as compared to 42 days exposure. In a chronic model of 180 days, Liv.52 normalised the blood ethanol and acetaldehyde levels in a dose- related manner. These observations are in agreement with our previous findings in chronic alcohol users. These bioassay findings could be effectively employed to evaluate the comparative efficacy of various polyherbal formulations on ethanol metabolism.

The effect of phaseolinone, a phytotoxin produced by the fungus Macrophomina phaseolina, on mice was investigated. Repeated injection over a period (2 to 4 g/kg body weight divided into 45 injections) of SO days of the toxin in adult mouse induced anaemia; a significant decrease of haemoglobin content and RBC- count of blood and considerable enlargement of spleen were observed. The mitotic index of bone marrow cells was reduced. Histological study of liver and kidneys showed no change. The hematopoietic tissue region was enlarged in spleen. The 50% lethal dose (LD50) was found to be 0.98 g/kg of mouse. Infant mice were more susceptible to this toxin. Repeated injection killed a considerable percent of animals and reduced the growth rate of survivors.

Monocrotophos, an organophosphate pesticide, was tested for its toxicity on female reproductive performance using rats as an experimental subject. Toxic effects in maternal rats included lower body weights and resorptions. Fertility and parturition indices were reduced in dose dependent fashion. However, gestation index was not affected. Viability and lactation indices were highly reduced in rats of high dose group. Birth weight and crown-rump length of pups in high-dose group were significantly less, with no effect on average litter size.

Effect of human placental extract (placentrex) was investigated on immune system of rabbits as well as human volunteers. In rabbits widal agglutination test using typhoid-H antigen and DNCB & tuberculin skin sensitivity were performed as measurement of humoral and cell mediated immunity. In human volunteers humoral immunity was evaluated by immunoglobulin (IgG, IgM and IgA) estimation using tripantigen plates and the cell mediated immunity was assessed by total lymphocyte count and Tcell counts. In rabbis significant rise in H-antibody titre and increase in grades of sensitivity against DNCB and tuberculin were observed. Likewise in human subjects an increase in serum immunoglobulin as well as total lymphocyte and T-cell counts were observed. These results suggest that placentrex is immunostimulant for humoral and cell mediated immunity in animals as well as human subjects. The finding may be of immense significance for restoring dysfunction of B and T cell lymphocytes.

The effects of morphine on gastrointestinal transit and castor oil diarrhea were studied in rats. These were antagonised by naloxone but not by the ATP-dependent potassium channel blocker glibendamide. Glibenclamide also failed to antagonise the antidiarrhoeal action of the peripherally acting opioid, loperamide. This suggests that the intestinal actions of morphine unlike its analgesic action are probably not mediated via the glibenclamide - sensitive potassium channel.

Phencyclidine (PCP). a psychotomimetic drug, interferes with glutamate transmission at the N-methyl-D-aspartate receptors in the central nervous system and precipitates psychotic reaction in humans which are similar to schizophrenia. The present study investigates whether surgical removal of the olfactory bulbs (0B) in rats could produce an effect or a deficit in the NMDA receptors in the olfactory bulbectomised animals following an acute challenge with a single high dose of PCP (10 mg/kq, i.p.) in comparison to Sham operated animals. PCP treatment produced an increase in home cage locomotor activity in both the 0B and Sham animals over a 3 hour period. The increase in locomotor activity was slightly higher in Sham operated animals than the OB animals. As regards to stereotyped behaviours, PCP produced various effects on behaviours in the OB and Sham animals; grooming, rearing, and falling on the sides was suppressed and chewing totally disappeared, whereas circling and head rolling was increased in the two groups, even though the suppression and increase in behaviours did not reach significance in both groups. It can be concluded that olfactory bulbectomy did not alter the NMDA receptors activity.

The antidermatophytic activity of the aqueous and ethanolic extracts of Neem (Azadirachta indica) leaves was investigated against 88 clinical isolates of dermatophytes by agar dilution. The isolates included Microsporum canis (50), M.audouinii (5), Trichophyton rubrum (6), Tmentagrophytes (5), T.violaceum (12), T.simii (5) T.verrucosum (1) T.soudanense (l), T.erinacei(1) and Epidermophyton floccosum (2). The results were compared with the minimal inhibitory concentrations of ketoconazole. The ethanolic extract was found to be more active inhibiting 90% (MIC 90) of the isolates at a concentration of 100 ug/ml. The MIC 50s and MIC 90s of the aqueous extract were 500 and > 500 ug/ml whereas the values for ketoconazole were 1 and 2.5 ug/ml respectively.

Extracts of Artemisia japonica, Artemisia maritima. Artemisia nilegarica in ethanol and light petroleum were tested for antimalarial activity.In vivo studies were carried out in mice using the Rane test. All the compounds prolonged survival time of mice as compared to control mice in the dose range of 640-320 mg/kg subcutaneusly. Chloroquine sensitive (FDL-Rl) strain of Plasmodium falciparum was used for in vitro studies. All the three compounds inhibited schizont maturation in concentration dependent manner in the range of 2.5 (g to 40 (g per 10 (g blood.

Disposition of (-)-norepinephrine (NE) and (-)-epinephrine (E) in duodenum of chicken (WLH) was studied using oil immersion technique. The relative rate of different routes of disposition of catecholamines was in the following order: for (-)- NE, COMT ( MAO ( uptake;! (uptake1; for (-)-E, COMT a uptakes ( uptake1 ( MAO. The role of enzymatic degraduation is almost equal to that of uptake processes for both (-)-NE and (-)-E. The uptake mechanisms do not appear to be an efficient route of disposition of catecholamines in this tissue.

Coleonol, a diterpene isolated from Coleus forskohlii which directly activates the adenylate cyclase and raises intracellular cyclic AMP levels in a variety of tissues, was studied for its effect on passive cutaneous anaphylaxis (PCA) and mast cell stabilizing activity. Coleonol has shown significant anti-PCA and mast cell stabilizing activity. However it was observed that coleonol is poorly absorbed when given orally. One of its derivative, coleonol hemisuccinate has been shown to be absorbed well when given orally.

Acute peripheral administration of methyldopa (20 mg/kg, i.p.) attenuates drinking response in rats to acute peripheral administration of either isoproternol (25(g/kg bw, s.c.) or hypertonic saline (5 ml/kg bw, i.p.) solution. This antidipsogenic action was not different from that of acute peripheral administration of clonidine (12 (g/kg bw, i.p.). These results suggest that methyldopa has antidipsogenic effect similar to clonidine and support the view that alpha2 adrenoceptors on neuraxis are involved in mediating this effect.

Biokinetics of cefazolin (CFZ) after single dose i.m. at the dose of 30 mg/kg was studied in afebrile and febrile goats. The mean cpmax of CFZ was higher (33.00 ( 2.14 (g ml-1) in afebrile as compared to that in febrile goats (19.59 (1.93 (gml-1). However, the tcpmer remained the same (4.0 h) in both the groups. The t1/2( mean value was significantly (P < 0.05) longer in the febrile goats (1.42 ( 0.14 h) as compared to that in the normal (1 .OO ( 0.04 h). The average AUC was significantly (P < 0.01) larger in normal goats (62.88 ( 4.30 (g ml-1) than that in the febrile goats (47.70 ( 2.61 (g ml-1). The dosage regimen of CFZ calculated on the basis of relevant biokinetic parameter under febrile situation has been suggested.

lntraperitoneal administration of adenosine (10 mg/kg) enhanced the analgesic effect of tricyclic antidepressant (TCA) imipramine or amitriptyline in the tail flick test. Theophylline (50 mg/kg) or caffeine (50 mg/kg), purinoceptor antagonists, attenuated the analgesic response not only of TCA alone but also of adenosine and TCA combination. These results indicate that TCA induced analgesia may be mediated through adenosinergic system and thus provide new evidence for their interaction.