vasoactive-intestinal-peptide and Ischemic-Attack--Transient

We studied the effect of vasoactive intestinal peptide (VIP) on angiogenesis in the ischemic boundary area after focal cerebral ischemia. Adult male Sprague-Dawley rats underwent middle cerebral artery occlusion for 2 h. A single dose of VIP was given via i.c.v. injection at the beginning of reperfusion. Immunohistochemistry and Western blotting were performed to assay angiogenesis and brain levels of vascular endothelial growth factor (VEGF) protein, respectively. In addition, the expression of VEGF and its receptors (flt-1 and flk-1), as well as endothelial proliferation, was measured using rat brain microvascular endothelial cells. Immunohistochemical analyses revealed significant (P<0.05) increases in the numbers of bromodeoxyuridine (BrdU) positive endothelial cells and microvessels at the boundary of the ischemic lesion in rats treated with VIP compared with rats treated with saline. Western blotting analysis showed that treatment with VIP significantly (P<0.05) raised VEGF levels in the ischemic hemisphere. In addition, treatment with VIP increased flt-1 and flk-1 immunoreactivity in endothelial cells. In vitro, incubation with VIP significantly (P<0.01) increased the proliferation of endothelial cells and induced the expression of VEGF, flt-1 and flk-1 in endothelial cells. The stimulatory effect of VIP on the proliferation of endothelial cells was significantly (P<0.01) inhibited by SU5416, a selective inhibitor of VEGF receptor tyrosine kinase. Our data suggest that treatment with VIP enhances angiogenesis in the ischemic brain, and this effect may be mediated by increases in levels of VEGF and its receptors.

Topics: Animals; Brain; Cell Proliferation; Cells, Cultured; Endothelial Cells; Ischemic Attack, Transient; Male; Microvessels; Neovascularization, Physiologic; Rats; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2; Vasoactive Intestinal Peptide

A possible involvement of perivascular vasodilatory neuropeptides in subarachnoid haemorrhage (SAH) has been evaluated in man by measuring the levels of calcitonin gene related peptide (CGRP)-, substance P (SP)- and vasoactive intestinal peptide (VIP)-like immunoreactivity (LI) in the cranial venous outflow and in CSF in 34 patients admitted to the hospital after an acute SAH. After operation with aneurysm clipping and nimodipine treatment, blood samples were taken from the external jugular vein (EJV) or cerebrospinal fluid (CSF) and analysed for neuropeptide levels with specific radioimmuno assays (RIA) during the postoperative course. The degree of vasoconstriction in the patients was monitored with Doppler ultrasound recordings bilaterally from the middle cerebral (MCA) and internal carotid arteries (ICA) following the EJV blood sampling every second day. The mean value of all CGRP-LI measurements in EJV during the entire course of SAH (n = 20) revealed a significantly higher level as compared to controls. The highest CGRP-LI levels were found in patients with the highest velocity index values (vasospasm). The relationship Vmean MCA/Vmean ICA was used as an index of vasoconstriction. In patients with MCA aneurysms (n = 10), a significant correlation (r = 0.65, p < 0.05) was found between the vasospasm index and CGRP-LI levels. There were no changes observed in the SP- and VIP-LI levels. Alterations in cerebrovascular tone induced by changing arterial CO2 tension or lowering of blood pressure (ketanserin infusion test) did not alter the levels of the perivascular peptides in the EJV. In addition, CGRP-, SP-, VIP- and neuropeptide Y (NPY)-LI were analysed in CSF in the post-operative course after subarachnoid haemorrhage (SAH) in 14 patients. The CSF VIP-LI was lower in SAH than in control (p < 0.05). The CGRP-LI level was measurable in SAH CSF but not in CSF of controls. In individual patients with marked vasoconstriction increased levels of CGRP-LI (up to 14 pmol/L) and NPY-LI (up to 232 pmol/L) were observed. The results of this study are in support of our hypothesis that there is an involvement of the sensory peptide CGRP in a dynamic reflex aimed at counterbalancing vasoconstriction in SAH.

Topics: Adult; Aged; Aneurysm, Ruptured; Blood-Brain Barrier; Brain; Calcitonin Gene-Related Peptide; Female; Homeostasis; Humans; Intracranial Aneurysm; Ischemic Attack, Transient; Jugular Veins; Male; Middle Aged; Postoperative Complications; Subarachnoid Hemorrhage; Substance P; Ultrasonography, Doppler, Transcranial; Vasoactive Intestinal Peptide; Vasoconstriction; Vasodilation

The effect of acute cerebral occlusion on the distribution of cerebral perivascular nerves containing catecholamine, neuropeptide Y, and vasoactive intestinal peptide was studied in the three commonly used rat models of cerebral ischemia: Unilateral permanent middle cerebral artery (MCA) occlusion induced with an intraluminal thread technique; unilateral MCA occlusion produced by extraluminal electrocoagulation of the MCA; and transient arterial occlusion of the whole brain induced extracranially by the four-vessel clasp occlusion method for 30 minutes. Animals were sacrificed 3 days after occlusion and the distribution of the perivascular nerves of the MCA studied. Intraluminally occluded MCAs showed a similar distribution of perivascular nerves to those of contralateral and sham-operated MCAs. Extraluminally occluded MCAs demonstrated a marked decrease in perivascular nerves containing catecholamine and peptides while the contralateral MCAs showed normal distribution of the nerves. Extracranial occlusion caused no discernible change in the distribution of perivascular nerves in occluded and sham-operated animals. This study indicates that the different methods of cerebral arterial occlusion have variable effects on the perivascular innervation. Arterial occlusion induced by intraluminal or transient extracranial procedures does not impair cerebral perivascular innervation at least up to 3 days post-occlusion. In contrast, cerebral arterial occlusion by extraluminal electrocoagulation diminishes the perivascular nerves around the occluded cerebral artery.

Topics: Animals; Catecholamines; Cerebral Arteries; Cerebral Infarction; Ischemic Attack, Transient; Male; Microscopy, Fluorescence; Nerve Fibers; Neuropeptide Y; Rats; Rats, Sprague-Dawley; Vasoactive Intestinal Peptide

In eight patients carotid angiography was required for evaluation of transient neurological attacks. Cerebral blood flow results, angiography and clinical observations subsequently suggested the diagnosis of migraine. We measured plasma concentrations of substance P(SP), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP) in repeated blood samples obtained from the carotid artery and the internal jugular vein in conjunction with cerebral angiography followed by 4 to 6 repeated recordings of regional cerebral blood flow (rCBF) with the intracarotid Xenon-133 injection technique. This technique is known to induce attacks of migraine with aura in many sufferers. Four patients developed aura symptoms. In three this was succeeded by throbbing headache. Typical, migraine-related, focal hypoperfusion occurred in conjunction with the aura symptoms. The remaining four patients had no symptoms or rCBF changes. There were no systematic or statistically significant changes over time in arterial-venous plasma concentrations or in the release rates of any of the peptides. All migraineurs had an overall elevated mean CGRP value compared to control values from the literature. The overall plasma levels of the potent vasoconstrictor NPY were higher (p < 0.10) in the group that developed symptoms and rCBF changes (136 pmol/l) than in the non-symptomatic group (97 pmol/l). The difference in NPY levels could perhaps be associated with the focal rCBF decrease seen in the attack group.

Topics: Adult; Calcitonin; Calcitonin Gene-Related Peptide; Carotid Artery, Internal; Cerebral Angiography; Cerebrovascular Circulation; Female; Hemiplegia; Humans; Ischemic Attack, Transient; Jugular Veins; Male; Middle Aged; Migraine Disorders; Neuropeptide Y; Neuropeptides; Paresthesia; Radionuclide Imaging; Substance P; Vasoactive Intestinal Peptide; Vision Disorders; Xenon Radioisotopes

INTRODUCTION--Cerebral blood vessels are innervated by sympathetic nerve fibres storing neuropeptide Y (NPY), parasympathetic nerves storing acetylcholine, vasoactive intestinal peptide (VIP) and sensory afferent fibres containing calcitonin gene-related peptide (CGRP), substance P (SP) and neurokinin A. In experimental studies on subarachnoid haemorrhage (SAH) there are indications that perivascular peptides are involved. In the present study we have in man measured the levels of NPY, VIP, SP and CGRP in brain vessels of patients that have suffered a fatal SAH and compared this with the levels encountered in subjects that died of an extracerebral cause. MATERIAL AND METHODS--Vessels from patients who have died from SAH or nonSAH were obtained during autopsy performed within 24 hrs after death. The peptides were extracted and fractionated with reversed phase liquid chromatography (HPLC). The levels of NPY, VIP, SP, and CGRP were measured with radioimmunoassay. Vasomotor responses of human cerebral arteries were performed using a sensitive in vitro system. RESULTS--Human cerebral vessels contained NPY, VIP, CGRP and SP which eluted at the same positions as the authentic peptides. The level of CGRP was significantly lower (p < 0.01) in arteries removed from SAH patients as compared to control subjects. The level of SP was not changed, if anything it tended to be increased after SAH. The levels of NPY and VIP were not significantly altered after SAH. In isolated brain vessels alpha-CGRP was a potent vasodilator of arteries precontracted with whole blood, prostaglandin F2 alpha or endothelin. It had a poor effect on vessels precontracted with 60 mM potassium. CONCLUSION--The evidence suggest that the trigemino-cerebrovascular system, storing CGRP and SP, is to a differential degree involved in the pathophysiology of SAH in man and supports the hypothesis of an exhaustion of CGRP as one important factor in the development of late spasm occurring after SAH.

Topics: Adult; Aged; Brain; Calcitonin Gene-Related Peptide; Cerebral Arteries; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Neuropeptide Y; Subarachnoid Hemorrhage; Substance P; Vascular Resistance; Vasoactive Intestinal Peptide; Vasomotor System

Calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) are intrinsic vasodilatory substances contained in perivascular nerve fibers innervating large intracranial arteries. Effects of these substances on delayed cerebral vasospasm were examined using a rabbit model of experimental subarachnoid hemorrhage (SAH). Sixty-one anesthetized rabbits received intrathecal fresh arterial blood on day-1 and intrathecal administration of different doses of CGRP, VIP or distilled water on day-4. Prior to the treatment, caliber of the spastic basilar artery was 73.4 +/- 0.9% of pre-SAH values. Serial angiograms after treatment demonstrated that 10(-10)mol/kg of CGRP dilated the spastic artery to 117.1% of pre-SAH levels and that dilatory effect of CGRP continued up to 6 hours after treatment. VIP injection also brought arterial dilatation up to 114.9% of pre-SAH levels, although the duration of the effect was less than 3 hours. Intrathecal administration of CGRP or VIP showed no adverse effect on the systemic and neurological state of the animals. These results indicate that intrathecal CGRP and VIP have therapeutic potential in treating delayed cerebral vasospasm after subarachnoid hemorrhage. Further investigations are expected to extend the effect of CGRP and VIP.

Topics: Animals; Calcitonin Gene-Related Peptide; Disease Models, Animal; Eating; Injections, Spinal; Ischemic Attack, Transient; Rabbits; Subarachnoid Hemorrhage; Vasoactive Intestinal Peptide

Marked hyperemia accompanies reperfusion after ischemia in the brain, and may account for the propensity of cerebral hemorrhage to follow embolic stroke or carotid endarterectomy, and for the morbidity that follows head injury or the ligation of large arteriovenous malformations. To evaluate the contribution of trigeminal sensory fibers to the hyperemic response, CBF was determined in 12 symmetrical brain regions, using microspheres with up to five different isotopic labels, in four groups of cats. Measurements were made at 15-min intervals for up to 2 h of reperfusion after global cerebral ischemia induced by four-vessel occlusion combined with systemic hypotension of either 10- or 20-min duration. In normal animals, hyperemia in cortical gray matter 30 min after reperfusion was significantly greater after 20 min (n = 10) than after 10 min (n = 7) of ischemia (312 ml/100 g/min versus 245 ml/100 g/min; p less than 0.01). CBF returned to preischemic levels approximately 45 min after reperfusion and was reduced to approximately 65% of basal CBF for the remaining 75 min. In cats subjected to chronic trigeminal ganglionectomy (n = 15), postocclusive hyperemia in cortical gray matter was attenuated by up to 48% on the denervated side (249 versus 150 ml/100 g/min; p less than 0.01) after 10 min of ischemia. This effect was maximal in the middle cerebral artery (MCA) territory, and was confined to regions known to receive a trigeminal innervation. In these animals, substance P (SP) levels in the MCA were reduced by 64% (p less than 0.01), and the density of nerve fibers containing calcitonin gene-related peptide (but not vasoactive intestinal polypeptide or neuropeptide Y) was decreased markedly on the lesioned side. Topical application of capsaicin (100 nM; 50 microliters) to the middle or posterior temporal branch of the MCA 10-14 days before ischemia decreased SP levels by 36%. Postocclusive hyperemia in cortical gray matter was attenuated throughout the ipsilateral hemisphere by up to 58%, but the cerebral vascular response to hypercapnia (PaCO2 = 60 mm Hg) was unimpaired. The duration of hyperemia and the severity of the delayed hypoperfusion were not influenced by trigeminalectomy, capsaicin application, or the intravenous administration of ATP. These data demonstrate the importance of neurogenic mechanisms in the development of postischemic hyperperfusion, and suggest the potential utility of strategies aimed at blocking axon reflex-like mechanisms to red

Topics: Adenosine Triphosphate; Animals; Calcitonin Gene-Related Peptide; Capsaicin; Cats; Cerebrovascular Circulation; Female; Ganglionectomy; Hyperemia; Ischemic Attack, Transient; Male; Nerve Fibers; Neuropeptide Y; Pia Mater; Substance P; Trigeminal Ganglion; Vasoactive Intestinal Peptide

The involvement of noradrenaline (NA), neuropeptide Y, (NPY), 5-hydroxytryptamine (5-HT), acetylcholine (ACh) and vasoactive intestinal polypeptide (VIP) has been examined in the late phase of spasm after an experimental subarachnoid hemorrhage (SAH) in a rat model. Immunocytochemistry and radioimmunoassay of blood vessels from the circle of Willis did not show significant differences in NPY- and VIP-like immunoreactivity 2 days post SAH as compared to control vessels. The postjunctional effects of NA, NPY, 5-HT, ACh and VIP were studied two days after SAH using a sensitive in vitro system. NPY induced contractions were significantly (p less than 0.01) weaker (lower Emax) in SAH as compared to control rats while the relaxant responses to ACh and VIP were slightly increased after SAH. These observations reveal that in a rat model of SAH, with an approximately 20% in vivo constriction at two days, dynamic changes occur in cerebral artery reactivity despite any obvious change in sympathetic or parasympathetic perivascular nerve networks.

Topics: Acetylcholine; Animals; Basilar Artery; Fluorescent Antibody Technique; Ischemic Attack, Transient; Male; Neuropeptide Y; Norepinephrine; Radioimmunoassay; Rats; Rats, Inbred Strains; Serotonin; Subarachnoid Hemorrhage; Vasoactive Intestinal Peptide; Vasoconstriction

The effects of transient (30') forebrain ischemia (4 vessel occlusion model) on peptidergic neurons and astroglial cells in various diencephalic and telencephalic areas have been analyzed. The study was performed at various time intervals of reperfusion, i.e. 4 h, 1, 7 and 40 days. Neuropeptide Y (NPY), somatostatin (SRIF), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP) and arginine-vasopressin (AVP) immunoreactive (IR) neuronal systems and glial fibrillary acidic protein (GFAP)-IR glial cells have been visualized by means of the indirect immunoperoxidase procedure using the avidin-biotin technique. The analysis was performed by means of computer assisted microdensitometry and manual cell counting. At the hippocampal level a huge reduction of neuropeptide (CCK, SRIF, VIP) IR cell bodies was observed, still present 40 days after reperfusion. On the contrary, in the frontoparietal cortex the number of the neuropeptide (CCK, SRIF, VIP, NPY) IR neurons showed a decrease at 4 h, 1 and 7 days after reperfusion followed by a complete recovery at 40 days. A rapid reduction followed by an almost complete recovery (7 days after reperfusion) was also observed at striatal level where SRIF- and NPY-IR neurons were detected. A marked decrease of NPY-IR terminals was observed in the paraventricular and periventricular hypothalamic nuclei and in the paraventricular thalamic nucleus. AVP-IR was markedly reduced in the magnocellular part of the paraventricular nucleus throughout the analyzed period (7 days after reperfusion). GFAP-IR was increased in the hippocampal formation and neostriatum while a not consistent increase was observed at neocortical level. These data point to a differential recovery of peptide-IR and to a different astroglial response in the various brain areas after transient forebrain ischemia. Region-specific factors rather than factors related to neuronal chemical coding seems to play a major role in determining the vulnerability of neuronal populations to transient ischemia.

Topics: Animals; Arginine Vasopressin; Astrocytes; Cerebral Cortex; Cholecystokinin; Corpus Striatum; Electroencephalography; Glial Fibrillary Acidic Protein; Hippocampus; Immunohistochemistry; Ischemic Attack, Transient; Male; Neurons; Neuropeptide Y; Peptides; Rats; Rats, Inbred Strains; Somatostatin; Vasoactive Intestinal Peptide

Changes in the density of cerebroarterial nerve fibers containing calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP)-like substance, as well as changes in dilatory responses of isolated cerebral arteries to these neuropeptides, after subarachnoid hemorrhage (SAH) were examined in dogs. Moreover, the effects of these neuropeptides to the experimentally produced cerebral arterial spasm were also examined in dogs. SAH was produced by a single injection of fresh autologous arterial blood (1 ml/kg body weight) or double injection of arterial blood (0.5 ml/kg body weight, 48 hours apart) into the cisterna magna. Constriction of basilar artery was most prominent on Day 3 in the single injection model, and on Day 7 in the double injection model. The density of nerve fibers with CGRP-or VIP-like immunoreactivity (LI) was markedly decreased during 7-14 days or 3-7 days after SAH. Vasodilatory actions of CGRP and VIP to isolated basilar artery in vitro were markedly impaired during acute stage of post-SAH period and significantly enhanced during chronic stage of post-SAH period. Intracisternal bolus injection of 10(-10) mol/kg CGRP completely reversed cerebral arterial constriction on Day 3 of single injection SAH model, and intracisternal injection of 10(-11) to 2 x 10(-10) mol/kg CGRP reversed cerebral vasospasm dose-dependently. Intraarterial injection of CGRP could not reversed cerebral arterial constriction. The effects of VIP was much weaker than CGRP.

Topics: Animals; Calcitonin Gene-Related Peptide; Cell Count; Cerebral Arteries; Dogs; In Vitro Techniques; Ischemic Attack, Transient; Nerve Fibers; Subarachnoid Hemorrhage; Vasoactive Intestinal Peptide

The levels of vasoactive intestinal peptide (VIP) in three regions of rat brain were assayed in 62 rats. Bilateral common carotid artery ligation was done in 50 rats. Half an hour before ligation 26 rats were given 10 g/kg of Radix Salviae Miltiorrhizae (RSM); 24 rats were given same volume of normal saline as controls. A sham operation was done in 12 rats. Half an hour (n = 30) and 3 hours (n = 32) after operation, the rats were quickly decapitated. VIP levels were assayed in cerebral cortex, hippocampus and caudate nucleus. In salin-treated animals, VIP levels of cerebral cortex and caudate nucleus at 3 hour group were significantly decreased compared with the sham-operated group. No significant difference was found between RSM-treated and sham-operated groups. The preliminary results suggest that VIP may be involved in the pathophysiological procedures of cerebral ischemia and RSM may attenuate the dysfunction of VIP during cerebral ischemia.

Topics: Animals; Brain; Drug Combinations; Drugs, Chinese Herbal; Ischemic Attack, Transient; Male; Phenanthrolines; Plant Extracts; Rats; Rats, Inbred Strains; Salvia miltiorrhiza; Vasoactive Intestinal Peptide

Topics: Animals; Cerebral Cortex; Hippocampus; Ischemic Attack, Transient; Male; Neurons; Rats; Rats, Inbred Strains; Vasoactive Intestinal Peptide

Patients with normal-pressure hydrocephalus, multi-infarct dementia, and recent cerebral infarction had significantly lower vasoactive intestinal polypeptide (VIP) levels than age-matched controls (11 +/- 3 pmol/l, 17 +/- 4 pmol/l, 21 +/- 4 pmol/l, and 33 +/- 4 pmol/l, respectively). Three months after a shunt operation, the VIP levels had increased significantly in patients with hydrocephalus (54 +/- 13 pmol/l). VIP concentration in patients with senile dementia did not differ from that of controls.

Topics: Aged; Dementia; Humans; Hydrocephalus; Ischemic Attack, Transient; Middle Aged; Vasoactive Intestinal Peptide