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Biomedical subjects

F Sicuteri

Publications and source records attributed to F Sicuteri.

At least 55 records · Page 3Linked to original sources

Beneficial effect of capsaicin application to the nasal mucosa in cluster headache.

Capsaicin application to human nasal mucosa was found to induce painful sensation, sneezing, and nasal secretion. All of these factors exhibit desensitization upon repeated applications. The acute effects induced by capsaicin (300 micrograms/100 microliters) application to the nasal mucosa were studied in healthy volunteers and cluster headache patients. These effects were not different in both nostrils of cluster headache patients as well as in the single nostril of healthy controls. Likewise, the time course of desensitization to the painful sensation and nasal secretion induced by capsaicin applied for five consecutive days in control subjects was almost superimposable to those observed in the nasal mucosa of cluster headache patients. The number of spontaneously occurring attacks was significantly reduced in the 60 days after the end of capsaicin treatment. Whether the beneficial effect induced by capsaicin application to the nasal mucosa could be ascribed to a specific action on sensory neurons remains unknown.

Administration, Intranasal↗

Substance P in the human iris: possible involvement in echothiophate-induced miosis in cluster headache.

Substance P-like immunoreactivity (SP-LI) was measured by radioimmunoassay in iris, choroid, and retina obtained from men after death. Although present in different amounts, SP-LI, eluting as authentic SP or SP sulfoxide in the high-performance liquid chromatography system, was found in the three ocular structures. The retina contained higher concentrations of SP-LI than the iris and choroid. The possible functional involvement of iris SP was studied in 22 episodic cluster headache (CH) patients by using the anticholinesterase agent echothiophate iodide (EI), which also induces an atropine-resistant miosis, putatively due to release of SP from trigeminal sensory neurons. In CH patients EI eye drops instilled into both eyes provoked a prolonged miosis with a more marked response in the pupil of the symptomatic eye. It is proposed that the hyperfunction of SP-containing neurons may coexist with the previously documented sympathetic hypofunction in the innervation of the symptomatic pupil of CH.

Adult↗

Does anisocoria by clonidine reflect a central sympathetic dysfunction in cluster headache?

Local pharmacological manipulations of both pupils in persons with cluster headache (CH) have shown a reduced pain-side sympathetic activity. It is difficult to determine if this sympathetic defect is localized in the nuclei of the CNS and/or in peripheral neurons that innervate the pupil. This study demonstrates that in a CH group 2% tyramine (an intraneuronal norepinephrine releaser) instillation into both eyes induces an asymmetric and bilateral mydriasis with the onset of anisocoria characterized by a pupillary diameter being less on the pain-side eye. In addition, intravenous administration of 0.10 mg clonidine, an inhibitor of central sympathetic activity, causes a bilateral miotic response, which is more marked on the pain-side eye. In a healthy control group, clonidine induces a symmetric and bilateral miosis but less intense than that observed in both eyes of CH sufferers. In CH patients, pretreatment with clonidine augments the degree of anisocoria induced by tyramine instillation, increasing the mydriatic response only in the pain-free-side pupil. The hypothesis of a permanent sympathetic defect of the pain-side pupil expressing itself as a reduced sympathetic tone of CNS nuclei and peripheral neurons that innervate the pupil is proposed.

Adult↗

Secretion, pain and sneezing induced by the application of capsaicin to the nasal mucosa in man.

1. Topical application of capsaicin to the human nasal mucosa induced a burning sensation and sneezing. A dose-dependent seromucous nasal secretion was also observed. Capsaicin (75 micrograms) was more potent than methacholine (50 mg) in producing nasal secretion, while topical histamine (200 micrograms), substance P (135 micrograms) and calcitonin gene-related peptide (36 micrograms) did not induce rhinorrhea. 2. Pretreatment with either topical ipratropium bromide, systemic dexchlorpheniramine or indomethacin did not influence the effects induced by capsaicin. Topical pretreatment with lidocaine inhibited the painful sensation but failed to block the rhinorrhea. Desensitization to the effects of capsaicin occurred following 4-5 subsequent applications, and full recovery was observed within 30-40 days. 3. It is proposed that the effects of capsaicin in human nasal mucosa are due to excitation of primary afferent neurones that (a) convey burning and painful sensation, (b) evoke a sneezing reflex and (c) induce nasal secretion by releasing transmitter(s) from their peripheral terminals.

Administration, Intranasal↗

Antiandrogenic medication of cluster headache.

The effectiveness of cyproterone acetate, a synthetic steroid with antiandrogenic action, was tested in 40 (young, adult) males, suffering from episodic (29) and chronic (11) cluster headache. Previously a minority (15) cases had been unsuccessfully treated with lithium, the conventional therapy of this condition. The rationale for an antiandrogenic treatment in cluster headache was based on its well-known clinical characteristics: 1) about 90% male sex preference; 2) rarity of clinical manifestations in childhood and in old age as well as women, e.g. in subjects with low androgenic secretion if compared to young adult males; 3) altered levels (increased or reduced, according to different authors) of plasma testosterone. The parameters to evaluate the effects of treatment were those conventional ones: intensity, duration and frequency of attacks. Antiandrogenic treatment improved, with few exceptions, by a slight, moderate or large extent, the course of cluster headache in all patients. The efficaciousness was mainly evident in those cases (15) of episodic or chronic cluster headache, previously resistant to lithium.

Adult↗

Acute oral captopril inhibits angiotensin converting enzyme activity in human cerebrospinal fluid.

Angiotensin converting enzyme (ACE) activity in human plasma and cerebrospinal fluid (CSF), was measured by a fluorimetric method, following an acute oral dose (75 mg) of captopril. A decrease of approximately 60% in enzyme activity was observed in CSF, suggesting that the drug penetrates the blood/brain barrier (BBB) in sufficient amounts to inhibit the ACE in CSF. The activity of CSF enkephalinase, an enzyme present in human brain and inhibited in vitro by an elevated concentration of captopril, was, however, unaffected by the acute drug administration. It is proposed that the antihypertensive effect of captopril in humans may be due, at least in part, to the inhibition of ACE contained within brain structures.

Administration, Oral↗

In vivo 'enkephalinase' inhibition by acetorphan in human plasma and CSF.

Thiorphan, the potent inhibitor of 'enkephalinase', has shown some analgesic properties in experimental animals and in man. The possibility that the intravenous infusion of acetorphan, a prodrug of thiorphan (26 micrograms/kg per min for 60 min), can inhibit plasma and cerebrospinal fluid (CSF) enkephalinase in man in vivo was investigated. A decrease of approximately 65% in enzyme activity was observed in both plasma and CSF. Acetorphan did not induce any significant variation of plasma angiotensin-converting enzyme activity.

Amino Acids, Sulfur↗

Substance P and enkephalins: a creditable tandem in the pathophysiology of cluster headache and migraine.

Substance P, present in primary sensory neurones, seems to take part in nociceptive transmission within the trigeminal system. Substance P, released by peripheral axons of these neurones, induces vasodilatation, plasma extravasation, miosis, conjunctival and nasal congestion. All these effects bear some similarity to symptoms of cluster headache and migraine attack. Opiates and somatostatin inhibit the release of substance P from primary sensory neurones and relieve both pain and autonomic symptoms of cluster headache attack. Plasma substance P-like immunoreactivity was decreased during spontaneous attack of cluster headache and migraine and during histamine precipitated attack of cluster headache. Taken together these data suggest that substance P and endogenous opioids could be implicated in the pathophysiology of cluster headache and migraine.

Analgesia↗

Hypernociceptive syndromes and pharmacological inhibition of endogenous opioid degradation.

Endogenous opioid peptides, by modulating the release of sympathetic transmitters, may play a role in the pathogenesis of migraine and related headaches which are considered hypernociceptive syndromes. Hypoendorphinaemia has been demonstrated in migraine attack. Captopril, a drug able to potentiate morphine analgesia in rats and inhibit enkephalinase in animals and in man, improves the clinical course of migraine. In the present research the cerebrospinal fluid and plasma beta-endorphin (beta-EP) levels have been evaluated following a single oral dose of captopril. The drug increased plasma beta-EP levels in migraine sufferers, and these data may be relevant in the mechanism of action of this drug in migraine and related headaches.

Captopril↗

Analgesizing effect of a methyl donor (S-adenosylmethionine) in migraine: an open clinical trial.

The long term administration of a methyl donor (S-adenosylmethionine, SAM) relieves pain in migraine sufferers. The benefit arises gradually and long-term treatment is required for therapeutic effectiveness. Since SAM is an almost ubiquitous methyl donor in many biological systems, an explanation of this peculiar therapeutic effect is only speculative. The activity of SAM on 5-hydroxytryptamine turnover is the most reasonable interpretation of the results.

Adolescent↗