We characterized a new iodinated, high affinity, linear V1a vasopressin antagonist, phenylacetylD-Tyr(Et)Phe-Gln-Asn-Lys-Pro-Arg-Tyr-NH2. The antagonist bound specifically to the V1a vasopressin receptor in crude rat liver membranes with an apparent Kd value of 0.168 nM. This affinity is approximately 1 order of magnitude greater than that of the natural agonist, vasopressin. The inhibitory act...

It has been reported that ketamine as an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist has also non-NMDA receptor antagonist properties. We recently found that ketamine (20 ?M) affected differently induction of NMDA receptor-mediated long-term potentiation (LTP) when administered 30 min prior to tetanic Primed-Bursts (PBs) stimulation. On the other hand, ketamine also influenced...

PURPOSE To determine whether systemic application of propranolol, a nonselective beta-adrenergic receptor antagonist, with an osmotic pump will decrease the b-wave amplitude of the electroretinogram (ERG) and increase insulin-like growth factor (IGF)-1 receptor signaling. METHODS Young rats at 8 weeks of age were treated with saline, phentolamine, a nonselective alpha-adrenergic receptor anta...

The aim of this study was to investigate the unknown effects 17β-estradiol (E2) on ureteral contractility and receptor mechanisms involved. By utilising isolated porcine distal strips, we observed that E2 (30–300 μM) a G protein-coupled estrogen specific agonist G-1 (30 both increased frequency phasic contractions ureter (P<0.05). also decreased maximum amplitude these antagonist G-36 (10 rever...

The cytokine channel’s mechanism for self-regulation involves the application of antagonistic cytokines that are synthesized to connect receptors and release soluble receptors. very first receptor antagonist was naturally present interleukin-1 (IL-1Ra). IL-1Ra protein forms disinfected from supernatants cultured monocytes on stacked IgG. family IL-1 consists IL-1α, IL-1β IL-1Ra. Human regulate ...

In the present study, the effect of GABA (γ-aminobutyric acid) receptor agonists and antagonists on morphine-induced antinociception was investigated in formalin test in rats. Intraperitoneal (i.p.) injection of different doses of morphine (1, 3, 6 and 9 mg/kg) and intracerebroventricular (i.c.v.) injection of different doses of muscimol (0.5, 1 and 2 g/rat) or baclofen (0.25, 0.5 and 1 g/rat) ...

Huh, Joon, Garrett J. Gross, Hiroshi Nagase, and Bruce T. Liang. Protection of cardiac myocytes via d1-opioid receptors, protein kinase C, and mitochondrial KATP channels. Am J Physiol Heart Circ Physiol 280: H377–H383, 2001.—The objective of the present study was to investigate the role of d1-opioid receptors in mediating cardioprotection in isolated chick cardiac myocytes and to investigate w...

Selective Endothelin Receptor Involvement in the Development of Colorectal Cancer and Liver Metastases Endothelin-1 (ET-1), a vasoactive peptide with mitogenic qualities, is over­ expressed in the plasma of patients with colorectal cancer (CRC) and liver metastases. Its actions are mediated via two G-protein linked receptors, ETA and ETb. This study (i) examined the effect of ET-1 and its recep...

in the present study, the effects of intracerebroventricular (icv) injections of histamine, chlorpheniramine (h1-receptor antagonist) and ranitidine (h2-receptor antagonist) were investigated on visceral nociception induced by an intraperitoneal (ip) injection of acetic acid in rats. the latency time to the beginning of the first abdominal wall contraction (the first writhe) was recorded and th...

macrophages and t-lymphocytes are involved in immune response to mycobacterium tuberculosis. macrophage produces interleukin (il)-1 as an inflammatory mediator. il-1 receptor antagonist (il1-ra) is a natural antagonist of il-1 receptors. in this study we aimed to examine the possible association between the variable number of tandem repeats (vntr) of the il-1 receptor antagonist (il1rn) gene an...