Methods. Changes in isometric tension were recorded in helical strips of the arteries, and the presence of perivascular nerve containing NADPH diaphorase was histochemically demonstrated. Results. Nicotine (10~ M, EOA and IOA) and transmural electrical stimulation (5 Hz, EOA) produced a slight or no contraction followed by a moderate relaxation in the strips contracted with prostaglandin F2a. T...

INTRODUCTION AND METHODS. Nitric oxide (NO) has recently emerged as a major modulator of carotid body (CB) chemoreception. This is evidenced by functional and morphological studies. Chemosensory activity is inhibited by NO agonists and disinhibited by antagonists in both in situ and in vitro preparations (1, 2). At the light microscopic level, the NADPH-diaphorase (NADPH-d)/nitric oxide synthas...

DT-diaphorase catalysed the reduction of 1,4-naphthoquinones with hydroxy, methyl, methoxy and glutathionyl substituents at the expense of reducing equivalents from NADPH. The initial rates of quinone reduction did not correlate with either the half-wave reduction potential (E1/2) value (determined by h.p.l.c. with electrochemical detection against an Ag/AgCl reference electrode) or the partiti...

Reduction of 2,5-diaziridinyl-3,6-bis(carboethoxyamino)-l,4-benzoquinone (diaziquone; AZQ) by purified rat hepatic DT-diaphorase »as NADH and enzyme dependent and was inhibited by prior boiling of the enzyme or by dicumarol. Under aerobic conditions some of the hydroquinone (AZQH2) formed by reduction oxidized to regenerate AZQ and an approximate 1:1 stoichiometry was observed between V/(.)l I...

Comparative studies on the nervous system revealed that nitric oxide (NO) retains its function through the evolution. In vertebrates NO can act in different ways: it is released solely or as a co-transmitter, released from presynaptic or postsynaptic site, spreads as a volumetric signal or targets synaptic proteins. In invertebrates, however, the possible sites of NO release have not yet been i...

Copper (Cu) toxicity on plants has become a major problem with increasing agricultural and environmental pollution. The effect of Cu on NADPH-diaphorase (NADPH-d) activity, commonly employed as a marker for nitric oxide synthase (NOS) activity and nitric oxide (NO) production, was investigated in root tips of Vicia faba L. We found that Cu stress stunted root growth and development of root hair...

The effects of protein malnutrition on the quantitative aspects of the myenteric plexus in the ileum of adult Rattus norvegicus were assessed. Thirty 90-day-old rats were divided into two groups: Control Group (CG, n=15) and Experimental Group (EG, n=15). The CG received 26% protein chow and the EG received 4% protein chow for 90 days. At the end of the experiment, the animals from the CG weigh...

reductase activity (MHR), measured by the Hegesh assay, decreases as normal red cells age. This probably accounts for the slighlty increased concentration of methemoglobin in older red cells. Exaggeration of normal MHR age lability was demonstrated in several individuals with various molecular abnormalities of NADH-diaphorase and was associated with more striking accumulation of methemoglobin i...