Vasopressin histamine effects

A number of studies have investigated the effects of peripheral neurotransmitters and peptides on the regulation of NGF production and secretion by isolated organs or cells. For example, Hellweg et al. (1988) examined the influence of many agents on the release of NGF into the medium of cultured irides. Addition of neuropeptide Y, substance P, vasopressin, somatostatin, vasoactive intestinal polypeptide, neurotensin, serotonin and histamine all failed to change NGF levels. However, as these experiments were carried out in serum that may have resulted in maximal stimulation of the NGF gene, only inhibitory effects may have been detectable. Indeed, noradrenaline and dopamine were shown to be inhibitory. 

Female rats kept under controlled environmental conditions were given a single intraperitoneal injection of saline solutions of isoproterenol (80 pg), epinephrine (80 or I60 pg), norepinephrine (80 or 160 p.g), dopamine (l mg), vasopressin (500 mU), histamine (300 jig), or 0.9 normal saline (0.2 ml). Throughout this paper all doses are expressed as weight units of free base. Ten minutes after the injection they were decapitated and the plasma separated ffom the pooled heparinized blood, was frozen and stored at -12 C until assayed for its ACTH content. The results as shown in Table 1, indicate that norepinephrine is more potent than epinephrine which is in turn more potent than isoproterenol in stimulating ACTH secretion, and that dopamine, histamine, and vasopressin in larger amounts have a similar effect. Since the potency of the catecholamines in this respect appeared to be... 

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