Simone Marabini

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 μg) was more potent than methacholine (50 mg) in producing nasal secretion, while topical histamine (200 μg), substance P (135 μg) and calcitonin gene‐related peptide (36 μg) 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.

Pain relief by somatostatin in attacks of cluster headache

Abstract The pain relieving effect of somatostatin treatment during 72 attacks of cluster headache in 8 male patients was compared to treatment with ergotamine or placebo in a double‐blind study. Infusion of somatostatin (25 &mgr;g/min for 20 min i.v.) reduced the maximal pain intensity and the duration of pain significantly compared to placebo treatment, and to a degree comparable to ergotamine tartrate treatment (250 &mgr;g i.m.). The results obtained provide new information concerning the possible mechanism of cluster headache attacks and suggest a new therapeutic approach.

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

Abstract: 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 μg/100 μl) 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.

Lowered circannual urinary melatonin concentrations in episodic cluster headache

The circannual secretion of melatonin in 14 Swedish and 15 Italian patients suffering from episodic cluster headache was compared with 14 Swedish and 15 Italian healthy controls matched for sex and age. Overnight samples of urine were collected once a month from 8 to 14 months and kept at -20° C until analysed with RIA. The melatonin concentrations in nocturnal urine were permanently low in cluster headache and there was no consistent change of the melatonin concentration in relation to cluster periods occurring during the study. There was no definitive circannual or infraannual rhythmicity of melatonin in patients or controls. Multiple analysis of variance with repeated measurements showed a significant effect of disease (p < 0.05), but not of time. Sex, geographical location, age, and smoking also had significant effects (p < 0.001) on the melatonin concentrations. Lower melatonin levels in cluster headache patients than in controls may in part be related to a larger number of smokers in the patient group. The relation between tobacco use and melatonin should be further studied.

Preventative effect of repeated nasal applications of capsaicin in cluster headache

&NA; Preliminary studies have shown that repeated nasal applications of capsaicin prevented the occurrence of cluster headache attacks. The present study was designed to verify the difference in efficacy of treatment with nasal capsaicin, depending on the side of application. Fifty‐two patients affected by episodic form were divided into 2 groups, one receiving the treatment on the same side where the attacks occurred (ipsilateral side), the other on the controlateral side. Eighteen patients with a chronic form alternately received both ipsilateral and controlateral treatments. Seventy percent of the episodic patients, treated on the ipsilateral side, showed a marked amelioration whereas no improvement was noted in the patients treated on the ontralateral side. The efficcy of ipsilateral treatment was emphasized by the results obtained in chronic patients. However, in these patients, the maximum period of amelioration lasted no more than 40 days. The differnce between the effects of the 2 treatments (contralateral and ipsilateral) was statistically significant in both episodic and chronic sufferers. The efficacy of repeated nasal applications of capsaicin in cluster headache is congruent with previous reports on the therapeutic effect of capsaicin in other pain syndromes (post‐herpetic neuralgia, diabetic neuropathy, trigeminal neuralgia) and supports the use of the drug to produce a selective analgesia.

Substance P Theory: A Unique Focus on the Painful and Painless Phenomena of Cluster Headache

SYNOPSIS

Effects of capsaicin on the metabolism of rheumatoid arthritis synoviocytes in vitro.

The effects of capsaicin, the ingredient of hot pepper, on rheumatoid arthritis synoviocytes have been studied. Capsaicin was shown to have a direct action on the metabolism of synovial cells. Thus at 10(-6) mol/l and at higher doses DNA synthesis was restored to the control level. Capsaicin at both doses induced an increase in the synthesis of collagenase and at the lower concentration (10(-8) mol/l) only of prostaglandins. These results indicate that the different effects of capsaicin on cellular proliferation and on metabolic activities are dependent on dose. The responses seen in rheumatoid arthritis synoviocytes in vitro might not be mediated by tachykinins if the synovial tissue is still able to produce neuropeptides in the absence of neuronal afferents. These results suggest that capsaicin, in addition to its direct action on the afferent nervous fibres and the consequent release of tachykinins, may also have a direct action on the cells. The mechanisms by which capsaicin stimulates DNA synthesis and production of collagenase and prostaglandin E2, in a manner dependent on dose, remain to be determined.

Collagenase synthesis of rheumatoid arthritis synoviocytes: dose-dependent stimulation by substance P and capsaicin.

The synthesis and release of collagenase in the presence of the neuropeptide substance P (SP) and capsaicin, were investigated in vitro using identical synoviocyte cultures from patients with rheumatoid arthritis (RA). On average 10(-12) M SP augmented statistically significantly the collagenase production by approximately a factor of five. An increase in the concentrations up to 10(-6) M SP resulted in a decreased collagenase synthesis, which, however, was still above the level of that of the untreated synoviocytes. Capsaicin, a homovanillic acid derivative that acts as a releaser of SP from primary afferent neurons, caused a strong stimulation of collagenase production and release at 10(-8) and 10(-6) M (about 7 times the amount of the control). With increasing concentrations up to 10(-3) M capsaicin this effect diminished continuously. The experiments clearly show that in RA synoviocytes in vitro SP and capsaicin in low concentrations act as potent inducers of the synthesis and release of collagenase.

A pharmacological approach to the analgesizing mechanism of somatostatin in cluster headache.

SummaryVasodilatation, conjunctival and nasal edema as well as miosis are symptoms associated with cluster headache (CH) attacks. Similar symptomatology is caused by substance P (SP) release from peripheral trigeminal nerve endings. The symptomatic effect of somatostatin (SRIF) during CH attacks was attributed to the inhibition of SP release from trigeminal neurons. This study was designed to evaluate both the vascular effect of SRIF on the dorsal hand vein and SRIF plasma levels prior to and after subcutaneous and intranasal administration in CH patients. A powerful venoconstriction and tachyphylaxis were demonstrated when SRIF was administered both as bolus and infusion. Plasma levels of SRIF in CH sufferers were lower than in control subjects. Subcutaneous and intranasal SRIF administrations induced maximal plasma levels after 5 and 10 min, respectively. These data suggest that SRIF plays an important role during CH attacks; however, its exact mechanism of action is still to be defined.

Somatostatin for Cluster Headache Attack

Cluster headache (CH) is a hemicraniofacial painful syndrome characterized by ip-silateral miosis and various vasomotor phenomena such as vasodilatation, salivation, nasal secretion, lacrimation and conjunctival congestion. A subpopulation of primary afferent neurons, projecting to the substantia gelatinosa in the spinal cord and to the corresponding area in the nucleus caudalis of the trigeminal nerve was shown to contain somatostatin (SRIF) and substance P (SP). The role of SRIF remains unclear, while that of SP is in the mediation of the antidromic vasodilatation. SP also appears to be the transmitter of pain signals [9]. Opiates and SRIF were capable of blocking the release of SP from both peripheral [2, 11] and central [13] nerve endings. SP induces miosis, edema of the nasal mucosa, vasodilatation. This striking similarity between SP function, trigeminal “topography,” and CH symptoms leads us to try SRIF as a symptomatic therapeutic agent in CH attack.