Disease relevance of VIP

• Combinations of IBMX plus nicotine, VIP, or histamine also synergistically enhanced proenkephalin synthesis, with no further elevation when the cells were also pretreated with pertussis toxin [1].
• Time-course experiments revealed that the inhibitory effects on contraction and motility were transient and that the cells gradually regained their activity, such that, when culture time was prolonged to 120 h, a stimulatory effect by VIP on bone resorption was observed [2].
• Since VIP is found in nerve terminals and the ganglion cells within the adrenal medulla, this peptide could be an endogenous regulator of adrenal enkephalin gene expression [3].
• In unanesthetized, unstressed rats with chronic catheters, 33 micrograms VIP/100 g body weight failed to alter triiodothyronine (T3) or thyroxine (T4) levels and did not affect the thyroid secretory response to a submaximal dose of bovine TSH [4].
• We conclude that the differential response of hamster and human pancreatic cancer to VIP treatment may be due to the presence or absence of VIP receptors [5].

High impact information on VIP

• Pretreatment with atropine completely blocked the bile-stimulated VIP release and significantly inhibited the caerulein-stimulated release of VIP [6].
• On the other hand, pretreatment with hexamethonium did not significantly decrease the VIP response by bile or caerulein [6].
• Intraileal administration of bile or intravenous caerulein, with or without intraduodenal ballooning, produced a significant increase of plasma VIP in the mesenteric vein [6].
• We studied the effect of intraileal administration of a 100-ml test meal, 100 ml of 5% glucose, amino acids, 10% Intralipos, or bile on canine plasma immunoreactive vasoactive intestinal polypeptide (VIP) levels in the mesenteric and femoral veins of dogs [6].
• Intraileal administration of the test meal, 5% glucose, amino acids, or 10% Intralipos induced no variation of mesenteric VIP [6].

Chemical compound and disease context of VIP

• Trifluoperazine and mellitin, two selective calmodulin inhibitors, failed to block the VIP-induced inhibition of bone resorption [7].
• Pertussis toxin pretreatment also increased proenkephalin synthesis in chromaffin cells exposed to vasoactive intestinal peptide (VIP) and 3-isobutyl-1-methylxanthine (IBMX) [1].
• Although neurally-evoked relaxation of the bovine retractor penis was impaired by hypoxia, relaxations produced by vasoactive intestinal peptide, prostaglandin E1, sodium nitroprusside or an inhibitory factor isolated from the bovine retractor penis were unaffected [8].

Biological context of VIP

• Secretin, another member of the glucagon-secretin family of peptides, which has only 30% sequence homology to VIP, was without effect [9].
• The results suggest that, like FSH, the stimulatory effect of the neuropeptide VIP on ovarian progesterone secretion involves regulation of P-450scc gene expression during functional maturation of the prepubertal ovary [10].
• The competitive binding curves for VIP analogs were similar in the bovine and rat vascular preparations [11].
• 3. In each of the above respects this intra-aortic infusion of VIP closely mimicked the effect of stimulation of the peripheral end of the right splanchnic nerve in these animals, as it also did by causing a substantial fall in adrenal vascular resistance in the absence, but not in the presence, of ACTH [12].
• Incubation of cells for 6 days with VIP in low serum medium showed similar changes in cell numbers, with growth being increased by doses in the 1 pM to 100 nM range and decreased at higher doses (greater than or equal to 100 nM) [13].

Anatomical context of VIP

• The effects of intravenous administration of caerulein on plasma immunoreactive VIP levels were examined, with or without intraduodenal ballooning, to rule out the effect of bile and pancreatic and gastric juice [6].
• In human small intestinal mucosa, trifluoperazine (0.1-0.5 mM) inhibited electrical responses to VIP and theophylline almost completely [14].
• In addition, hexamethonium bromide or atropine sulfate was given intravenously before the administration of bile or intravenous caerulein to study the role of the neural pathway on the release of VIP [6].
• To gain insight into its mechanism of action, the effect of VIP on the synthesis of the cholesterol side-chain cleavage enzyme complex was studied in ovarian granulosa cells from immature estrogen-primed rats [9].
• Time course studies indicated that the binding of 125I-VIP to digitonin extract was more rapid than to rat lung membranes [15].

Associations of VIP with chemical compounds

• It is suggested that a stimulatory action of VIP on the synthesis of ovarian progesterone may contribute to regulating the functional development of the ovary [9].
• Vasoactive intestinal peptide (VIP) has been identified in ovarian nerves and stimulates steroid secretion from immature ovaries [9].
• VIP-induced synthesis of the cholesterol side-chain cleavage enzyme complex was accompanied by a dose-related increase in cAMP accumulation and progestin formation [9].
• Peptide NH2-terminal histidine, COOH-terminal isoleucine, which has greater than 50% sequence homology of VIP, stimulated the synthesis of both proteins at approximately 50% of VIP effectiveness [9].
• A rapid soluble receptor assay was established to separate 125I-VIP-receptor complexes from free 125I-VIP, which entailed differential precipitation of the 125I-VIP-receptor complex with polyethylene glycol and bovine gamma-globulin [15].

Regulatory relationships of VIP

• It was concluded that PACAP from the VIP/secretin family may stimulate pancreatic exocrine secretion in conscious calves and a part of the pancreatic response to food intake can be mediated by PACAP [16].
• The marginal effects of large doses of nicotine on both cAMP accumulation and TH induction were blocked completely by hexamethonium but were also partially inhibited by the VIP antagonist [p-chloro-D-Phe6,Leu17]-VIP [17].
• Stimulation of VIP and substance P biosynthesis by forskolin was markedly enhanced by IL-1 alpha, while forskolin stimulation of enkephalin and neurotensin biosynthesis was unaffected [18].
• Pretreatment of the cells with nicotine, histamine, or vasoactive intestinal peptide to enhance the rate of proenkephalin synthesis failed to alter the time course of processing and had minimal effects on the distribution of products formed [19].

Other interactions of VIP

• Long-term, gene transcription of phenylethanolamine-N-methyltransferase (PNMT) is exerted by glucocorticoids, and gene transcription of Proenkephalin-A by agents such as histamine, angiotensin II and VIP that increase cyclic AMP (cAMP) [20].
• Two neuropeptides whose biosynthesis is regulated by PACAP include enkephalin and vasoactive intestinal polypeptide (VIP) [21].
• The possibility that vasoactive intestinal polypeptide (VIP) may facilitate the nicotine-mediated induction of adrenal medullary tyrosine hydroxylase (TH) was investigated with primary cultures (5-7 days in vitro) of bovine adrenal chromaffin (BAC) cells [17].
• IL-1 alpha amplified the effect of phorbol myristate acetate to increase the VIP content of chromaffin cells, but antagonized phorbol ester-induced elevation of neurotensin levels [18].
• In contrast to NPY, VIP was first found in the cortex [22].

Analytical, diagnostic and therapeutic context of VIP

• Sepharose 4B gel filtration chromatography was utilized to demonstrate the formation of specific binding complexes between 125I-VIP and solubilized receptors [15].
• VIP (10(-8)-10(-6) M) enhanced the response to electrical stimulation, while the contractile amplitude of the ciliary muscle to exogenous carbachol was not altered significantly by application of 10(-7)-10(-6) M VIP [23].
• Peptide histidine isoleucine, a VIP-related peptide, is also expressed concomitantly with VIP after treatment with phorbol ester [24].
• The distribution of VIP receptors was studied by autoradiography using [125I]-VIP [25].
• The distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine-enkephalin (LENK), and gastrin-releasing polypeptide (GRP) in the margin of the reticulo-omasal orifice, omasum, and omasal pillar of calves and cows was studied by immunohistochemistry [26].

References