The role of histamine H1-, H2- and H3-receptors was studied on neural transmission in ascending excitatory pathways of the guinea pig ileum. A two-compartment (oral and anal compartments) bath was used: ascending neural pathways were activated by electrical stimulation in the anal compartment and the resulting contraction of the circular muscle in the oral compartment was recorded. Drugs were a...

We studied the pharmacological characteristics of HSR-609 (3-[4-(8-fluoro-5,11-dihydrobenz[b]oxepino[4,3-b]pyridin-11- ylidene)- piperidino]propionic acid dihydrate), a novel amphoteric antiallergic agent, on the central nervous system (CNS). Its selectivity for the histamine H1-receptor and its ability to penetrate into the CNS were compared with those of typical antiallergic agents and the no...

To determine whether neuronal histamine influences development of histamine H-1 receptors in the rat brain, neonates were given diphenhydramine, an H-1 antagonist, daily for the first 21 days of postnatal life. In control rats, specific H-1 binding of [3H]mepyramine in whole brain was low at birth and increased progressively toward adult levels by the end of the 3rd week. Animals treated with d...

BACKGROUND Histamine has a short-term, transient, stimulating effect on endothelial nitric oxide synthase (eNOS) activity; however, long-term effects on eNOS have not been described yet. In addition, the vascular effect of histamine seems to depend critically on eNOS functionality. Therefore, we studied the effects of histamine on eNOS gene expression and function. METHODS AND RESULTS In huma...

The superior vestibular nucleus (SVN), which holds a key position in vestibulo-ocular reflexes and nystagmus, receives direct hypothalamic histaminergic innervations. By using rat brainstem slice preparations and extracellular unitary recordings, we investigated the effect of histamine on SVN neurons and the underlying receptor mechanisms. Bath application of histamine evoked an excitatory resp...

Objective: Crocin and safranal, as the major constituents of saffron, have many biological activities. This study investigated the effects of crocin and safranal on yawning response induced by intracerebroventricular (i.c.v.) injection of histamine in rats. Materials and Methods: In ketamine/xylazine-anesthetized rats, a guide cannula was implanted in the right ventricle of the brain and yawnin...