Biomaterial Database

Evidence against vasoactive intestinal polypeptide as the relaxant neurotransmitter in human cavernosal smooth muscle. 1993

R S Pickard, and P H Powell, and M A Zar

Department of Pharmacological Sciences, Medical School, University of Newcastle upon Tyne.

1. The putative role of vasoactive intestinal polypeptide (VIP) as the relaxant neurotransmitter in human cavernosal smooth muscle has been studied in isolated tissue preparations. 2. Consistent neurogenic relaxations were evoked by electrical field stimulation (EFS; 2-64 pulses/train, 0.8 ms pulse duration, 10 Hz). VIP (0.1-3 microM) relaxed cavernosal smooth muscle in a dose-dependent fashion. Relaxant responses to both EFS and VIP were reduced in tissue from impotent men. 3. Neurogenic relaxant responses were not diminished in the presence of the VIP-inactivating peptidase, alpha-chymotrypsin (alpha-CT, 2 units ml-1). In contrast VIP-induced relaxations were completely abolished. 4. Inhibition of nitric oxide synthase by NG-nitro-L-arginine (30 microM), and of guanylate cyclase by methylene blue (50 microM) caused highly significant reductions of neurogenic relaxant responses whereas VIP-evoked relaxations were unaffected. 5. It is concluded that VIP-evoked relaxations are not mediated by the NO-guanosine 3':5'-cyclic monophosphate (cyclic GMP) pathway and that VIP release is not essential for neurogenic relaxation of human cavernosal smooth muscle. VIP does not therefore act as the major relaxant neurotransmitter in this tissue.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008751	Methylene Blue	A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.	Methylthionine Chloride,Swiss Blue,Basic Blue 9,Chromosmon,Methylene Blue N,Methylthioninium Chloride,Urolene Blue,Blue 9, Basic,Blue N, Methylene,Blue, Methylene,Blue, Swiss,Blue, Urolene
D009126	Muscle Relaxation	That phase of a muscle twitch during which a muscle returns to a resting position.	Muscle Relaxations,Relaxation, Muscle,Relaxations, Muscle
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009569	Nitric Oxide	A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.	Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D010413	Penis	The external reproductive organ of males. It is composed of a mass of erectile tissue enclosed in three cylindrical fibrous compartments. Two of the three compartments, the corpus cavernosa, are placed side-by-side along the upper part of the organ. The third compartment below, the corpus spongiosum, houses the urethra.	Glans Penis,Penis, Glans
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D006152	Cyclic GMP	Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)	Guanosine Cyclic 3',5'-Monophosphate,Guanosine Cyclic 3,5 Monophosphate,Guanosine Cyclic Monophosphate,Guanosine Cyclic-3',5'-Monophosphate,3',5'-Monophosphate, Guanosine Cyclic,Cyclic 3',5'-Monophosphate, Guanosine,Cyclic Monophosphate, Guanosine,Cyclic-3',5'-Monophosphate, Guanosine,GMP, Cyclic,Guanosine Cyclic 3',5' Monophosphate,Monophosphate, Guanosine Cyclic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man