Many physiological functions of the stomach depend on an intact mucosal integrity; function reflects structure and vice versa. Histamine in the stomach is synthesized by histidine decarboxylase (HDC), stored in enterochromaffin-like (ECL) cells, and released in response to gastrin, acting on CCK(2) receptors on the ECL cells. Mobilized ECL cell histamine stimulates histamine H(2) receptors on t...

Histamine is a transmitter in the nervous system and a signaling molecule in the gut, the skin, and the immune system. Histaminergic neurons in mammalian brain are located exclusively in the tuberomamillary nucleus of the posterior hypothalamus and send their axons all over the central nervous system. Active solely during waking, they maintain wakefulness and attention. Three of the four known ...

Histamine H(3) receptors were first described in the eighties but finally cloned four years ago. They are G-protein coupled, mostly presynaptic, and are involved in the control of the synthesis and/or release of different neurotransmitters both in the central nervous system and the periphery. The availabiliy of specific ligands has permitted the study of potential therapeutic applications of ei...

  Objective(s): The present study investigated the effects of microinjection of histamine and histamine H1, H2, and H3 receptor antagonists, chlorpheniramine, ranitidine and thioperamide, respectively into the primary somatosensory cortex (PSC) on inflammatory pain.   Material and Methods: Two stainless steel guide canulas were bilaterally implanted into the PSC of anaesthetized rats. Inf...

The present study explored the interaction between histaminergic and opioidergic systems at the level of the hippocampus in modulation of orofacial pain by intra-hippocampal microinjections of histamine, pyrilamine (an antagonist of histamine H(1) receptors), ranitidine (an antagonist of histamine H(2) receptors), morphine (an opioid receptor agonist) and naloxone (an opioid receptor antagonist...

Effects of histamine per se along with its specific agonists and antagonists were studied on the skin melanophores of Hemidactylus flaviviridis to study the role of histamine receptors in pigmentation. Histamine and 2-methyl histamine induced powerful melanin aggregation effects, leading to paling of the skin through stimulation of H1 receptors. On the other hand, 4-methyl histamine, a specific...

Histamine influences several immune/inflammatory and effector functions in addition to its dominant role in type I hypersensitivity reactions. Histamine can selectively recruit the major effector cells into tissue sites and affect their maturation, activation, polarization, and other functions leading to chronic inflammation. Histamine also regulates monocytes, dendritic cells, T cells and B ce...