Spasmodic Response and Neurogenic Mechanism of Water Extract of Vernonia cinerea (L.) Less on Rat Duodenum.

Use of different agonists and antagonists for elucidating the mechanism of aqueous extract of Vernonia cinerea (L.) Less. on duodenal smooth muscle of female albino rat suggested the presence of an active ingredient in plant having spasmogenic response that has neurogenic mechanism on rat duodenal smooth muscle. The responses of extract were dose dependent and fully reversible on wash. The findings suggested that the extract responses mediate through agonistic action without blockade of any receptor enzyme. Extract possibly stimulates presynaptic cholinergic nerve endings to produce spasmodic response in rat duodenal smooth muscle.

Central noradrenergic & dopaminergic modulation of brewer's yeast-induced inflammation & nociception in rats.

The possibility of central noradrenergic and dopaminergic modulation of Brewer's yeast-induced peripheral inflammation was investigated in rats. Centrally administered noradrenaline (NA), amphetamine, which liberates NA and dopamine in the central nervous system and L-dopa, the precursor of dopamine significantly suppressed paw oedema. Conversely, the beta-adrenoceptor blocker, propranolol, catecholaminergic neuron degenerator, 6-hydroxydopamine (6-OHDA), dopaminergic antagonist, haloperidol and dopamine synthesis inhibitor, alpha-methyl para tyrosine (AMPT) augmented paw oedema. In addition, 6-OHDA and haloperidol produced significant reduction in pain threshold. The results of this study indicate that central NA and dopamine exert inhibitory effects on Brewer's yeast-induced peripheral inflammation.

Central modulation of Brewer's yeast-induced peripheral inflammation by neuropeptides bradykinin and substance P.

Possible modulation of the Brewer's yeast-induced peripheral inflammation by two central neuropeptides, bradykinin and substance P (SP), was investigated in rats. Centrally administered bradykinin significantly increased pedal oedema and pain threshold whereas, SP produced significant augmentation of oedema volume and nociception. The results of the present study indicate that central bradykinin exerts pro-inflammatory and analgesic effects whereas, central SP exerts pro-inflammatory and pro-nociceptive effects on Brewer's yeast-induced peripheral inflammation.