Long-Term Follow-up Study of Hospitalizations for Acute Coronary Syndrome in Kobe-City and Other Districts Under the Hyogo Smoking Ban Legislation　- A Nationwide Database Study.

BACKGROUND: Hyogo Prefecture has managed smoking ban legislation with partial restrictions in public places (Hyogo-L) since 2013. Previous studies have reported a significant decrease in admissions for acute coronary syndrome (ACS) in Kobe-city, but not in other districts of Hyogo Prefecture in the 2 years after Hyogo-L. The aim of the present study was to define the long-term effect of Hyogo-L.Methods and Results: The JROAD-DPC dataset was used to collect information on the number of hospitalizations for ACS in Hyogo Prefecture, and in Osaka-city without smoking ban legislation, from April 2013 to March 2020. Poisson regression analysis was performed to calculate incident rate ratios (IRRs) and 95% confidence intervals (CIs). ACS records of 3,101 in Kobe-city, 11,375 in areas of Hyogo Prefecture other than Kobe-city and 11,079 in Osaka-city were collected for admissions. The incidence of ACS reduced significantly over time in Kobe-city [IRR (95% CI); 0.96 (0.94-0.97)], but did not reduce in the others. The decrease in Kobe-city was observed in ACS patients without smoking, hypertension, and hyperlipidemia, but not in those with such risk factors. CONCLUSIONS: The long-term ACS reduction or non-reduction under Hyogo-L was determined at the initial period and the same scenario continued, supporting the importance of legislation and compliance with the smoking ban. The lowering effect was remarkable in ACS patients without risk factors such as non-smoking.

Consensus statement on smoking cessation in patients with pain.

Smoking is closely associated with the development of various cancers and tobacco-related illnesses such as cardiovascular and respiratory disorders. However, data are scarce on the relationship between smoking and both acute and chronic pain. In addition to nicotine, tobacco smoke contains more than 4000 different compounds. Although nicotine is not the sole cause of smoking-induced diseases, it plays a critical role in pain-related pathophysiology. Despite the acute analgesic effects of nicotine, long-term exposure leads to tolerance and increased pain sensitivity due to nicotinic acetylcholine receptor desensitization and neuronal plastic changes. The purpose of smoking cessation interventions in smoking patients with pain is primarily not only to reduce their pain and associated limitations in activities of daily living, but also to improve the outcomes of underlying pain-causing conditions and reduce the risks of tobacco-related disorders. This statement aims to summarize the available evidence on the impact of smoking on pain and to inform medical professionals of the significance of smoking cessation in patients with pain.

A practical guide for perioperative smoking cessation.

The perioperative management of patients who are smokers presents anesthesiologists with various challenges related to respiratory, circulatory, and other clinical problems. Regarding 30-day postoperative outcomes, smokers have higher risks of mortality and complications than non-smokers, including death, pneumonia, unplanned tracheal intubation, mechanical ventilation, cardiac arrest, myocardial infarction, and stroke. Given the benefits of smoking cessation and the adverse effects of smoking on perioperative patient management, patients should quit smoking long before surgery. However, anesthesiologists cannot address these issues alone. The Japanese Society of Anesthesiologists established guidelines in 2015 (published in a medical journal in 2017) to enlighten surgical staff members and patients regarding perioperative tobacco cessation. The primary objective of perioperative smoking cessation is to reduce the risks of adverse cardiovascular and respiratory events, wound infection, and other perioperative complications. Perioperative preparations constitute a powerful teachable moment, a "golden opportunity" for smoking cessation to achieve improved primary disease outcomes and prevent the occurrence of tobacco-related conditions. This review updates the aforementioned guidelines as a practical guide to cover the nuts and bolts of perioperative smoking cessation. Its goal is to assist surgeons, anesthesiologists, and other medical professionals and to increase patients' awareness of smoking risks before elective surgery.

Endothelium-dependent vasodilation in the cerebral arterioles of rats deteriorates during acute hyperglycemia and then is restored by reducing the glucose level.

PURPOSE: Acute hyperglycemia in patients with traumatic brain injury correlates with a poor neurological outcome. We investigated the endothelium function of rat cerebral arterioles during acute hyperglycemia and after reducing the glucose levels using insulin. We also examined whether or not oxidative stress was involved in the cerebral arteriole response to acute hyperglycemia. METHODS: In isoflurane-anesthetized, mechanically ventilated rats, we used closed cranial window preparation to measure the changes in the pial arteriolar diameter following the topical application of acetylcholine (ACh) or adenosine. We examined the pial arteriolar vasodilator response before hyperglycemia, during hyperglycemia, and after reducing the glucose level using insulin. After intravenous pretreatment with an NADPH oxidase inhibitor (apocynin or diphenylene iodonium), we reexamined the pial arteriolar vasodilator response following the topical application of ACh. RESULTS: Under control conditions, the topical application of ACh dose-dependently dilated the cerebral arterioles. The vasodilatory responses to topical ACh were impaired during hyperglycemia and improved after the administration of insulin. The vasodilatory responses to topical adenosine were not affected by the glucose levels. In the apocynin or diphenylene iodonium pretreatment group, the topical application of ACh dilated the cerebral arterioles during hyperglycemia. CONCLUSION: Acute hyperglycemia induces a dysfunction of the endothelium-dependent vasodilation of rat cerebral arterioles. The dysfunction can be reversed by improving the acute hyperglycemia and it can be prevented entirely by the administration of NADPH oxidase inhibitors. These results could suggest that controlling the glucose levels works protectivity to endothelium function of cerebral arterioles.

Results of a Prospective Study of Acute Coronary Syndrome Hospitalization After Enactment of a Smoking Ban in Public Places in Hyogo Prefecture　- Comparison With Gifu, a Prefecture Without a Public Smoking Ban.

BACKGROUND: Hyogo Prefecture is the 2nd prefecture in Japan, after Kanagawa, to enact a ban with penal code on smoking in public places, although the restriction is partial.Methods and Results:This study included consecutive patients with acute coronary syndrome (ACS) who were admitted to 33 major hospitals in the Hyogo District during the 12 months before implementation of the legislation and during the 24 months thereafter. Consecutive patients with ACS from Gifu Prefecture who were admitted to 20 major hospitals were enrolled as geographical controls. The number of ACS admissions did not change from the years 2012-2015 in both Hyogo District (1,774 in the pre-year, 1,784 in the 1st year, and 1,720 in the 2nd year) and Gifu Prefecture (1,226 in the pre-year, 1,174 in the 1st year, and 1,206 in the 2nd year). However, a clear reduction was observed in the subanalysis for Kobe City (895 in the preceding year, 830 (-7.3%) in the 1st year, and 792 (-11.5%) in the 2nd year), where adherence to the smoking ban was higher than in other Hyogo districts. CONCLUSIONS: The primary endpoint did not show a significant change. However, the subanalysis showed a significant decrease in ACS admissions in Kobe City. These results suggest that ACS reduction may depend on the degree of adherence to a smoking ban. (Circ J 2016; 80: 2528-2532).

Effects of topical and intravenous JM-1232(-) infusion on cerebrovascular reactivity in rats.

A novel short-acting benzodiazepine receptor agonist, JM-1232(-), has been shown to have a sedative/hypnotic effect and wide safety margin. However, its effect on cerebral vessels is not well known. Therefore, we investigated the cerebrovascular reactivity to topical and intravenous JM-1232(-) and during hypotension or hypercapnia with intravenous administration of JM-1232(-). We used a closed cranial window preparation to measure the changes of cerebral pial arteriolar diameters in isoflurane-anesthetized Sprague-Dawley rats. We first measured the direct effect of topical JM-1232(-). We then determined the effect of intravenous JM-1232(-) and then we measured the response to hypercapnia before and after JM-1232(-) infusion. Finally, we measured the reaction to stepwise induction of hypotension before and after JM-1232(-) infusion. Topical infusion of JM-1232(-) dilated pial arterioles. Intravenous infusion of JM-1232(-) changed pial arterioles by 4.5 ± 2.7 %, 5.0 ± 3.9 %, and -2.8 ± 2.6 % (at 0.1, 0.3, and 1.0 mg/kg/min, respectively). Hypercapnia dilated pial arterioles before and after JM-1232(-) infusion. The diameters of pial arterioles did not change during hypotension before or after intravenous JM-1232(-) infusion. These results indicate that topical JM-1232(-) has a dilative effect on pial arterioles and that intravenous administration of JM-1232(-) may not affect cerebrovascular reactivity to hypotension or hypercapnia.

[Survey of the preoperative smoking cessation in patients for elective surgery in a university hospital].

BACKGROUND: In 2006, we reported the smoking status of surgical patients, and the factors relating to preoperative abstinence from cigarettes. Recently implementation of smoke-free policies has increased in Japan. Therefore we performed preoperative interview of 1,124 patients scheduled for elective surgery in 2011 (during 6 months), and compared the results with those of the same interview of 1,968 patients in 2006 (during 12 months). METHODS: Anesthesiologists interviewed all patients using a standardized questionnaire regarding: medical history, smoking history, and awareness of the risks of perioperative smoking. RESULTS: Current smoking rate was not different between 2006 (7%) and 2011 (7%). It was more difficult to quit smoking preoperatively for female patients in 2011 (P = 0.030), and those with benign disease in both 2006 (P = 0.006) and 2011 (P = 0.050) [smoker vs ex-smoker (< three months)]. There was no improvement in awareness of the perioperative risk of smoking between 2006 and 2011. CONCLUSIONS: At present, the importance of perioperative smoking cessation has not been sufficiently well-known for the surgical patients. Health care workers should be more aware of the importance of informing patients that preoperative abstinence from cigarettes may decrease perioperative complications.

Preventive effect of varenicline on impairment of endothelial function in cerebral vessels induced by acute smoking in rats.

Preoperative smoking cessation is important for recovery from surgery without complications. Available evidence suggests nicotine replacement therapy could be safe and effective in the perioperative period. On the other hand, the newly developed selective nicotinic acetylcholine (ACh) receptor partial agonist, varenicline tartrate, is also effective as an aid for smoking cessation and helps people to stop smoking. During the transitional phase between the decision to stop smoking and actual smoking cessation, patients could use varenicline before undertaking smoking cessation. We have previously reported that acute cigarette smoking can cause impairment of endothelium-dependent vasodilation in cerebral vessels; thus, the use of varenicline before surgery in a patient who is still a smoker may not be safe with regard to endothelial function. Therefore, to assess the safety of varenicline in terms of endothelial function, we evaluated its effect on the acute smoking-induced impairment of endothelium-dependent cerebral vasodilation. In anesthetized Sprague-Dawley rats, we applied ACh topically to pial vessels; then, after administering intravenous varenicline or saline injection, we reexamined the ACh-induced vasodilator response both before and after smoking. Under control conditions, cerebral pial arterioles were dose-relatedly dilated by ACh. After smoking, 10(-5) M ACh constricted the arterioles following saline pretreatment (diameter -7.6 ± 1.8 %, n = 6), but induced dilation following varenicline pretreatment (diameter +15.3 ± 3.3 %, n = 6). Thus, varenicline may prevent the smoking-induced impairment of endothelium-dependent vasodilation in cerebral pial arterioles.

Smoking cessation after cancer diagnosis reduces the risk of severe cancer pain: A longitudinal cohort study.

BACKGROUND: Whether abstinence from smoking among cancer patients reduces cancer pain is still unclear. Opioids can act as a surrogate index for evaluating the incidence of severe cancer pain in countries where opioid abuse is infrequent. This study aimed to investigate whether changed smoking behavior after cancer diagnosis influences the incidence of severe cancer pain as determined by strong opioid use. METHODS: Using a large Japanese insurance claims database (n = 4,797,329), we selected 794,702 insured employees whose annual health checkup data could be confirmed ≥6 times between January 2009 and December 2018. We selected 591 study subjects from 3,256 employees who were diagnosed with cancer pain and had health checkup data at the year of cancer pain diagnosis. RESULTS: A significantly greater proportion of patients who continued smoking after cancer diagnosis ("current smoker", n = 133) received strong opioids (36.8%) compared with patients who had never smoked or had stopped before cancer diagnosis ("non-smoker", n = 383, 20.6%; p<0.05) but also compared with patients who had quit smoking after cancer diagnosis ("abstainer:", n = 75, 24.0%; p<0.05). In multivariable Cox proportional hazards regression analysis, abstainers had a significantly lower risk of receiving strong opioids than current smokers (hazard ratio: 0.57, 95% CI: 0.328 to 0.997). These findings were consistent across multiple sensitivity analyses. CONCLUSION: Our study demonstrated that patients who quit smoking after cancer diagnosis have a lower risk of severe cancer pain. This information adds clinical incentives for improving quality of life among those who smoked at the time of cancer diagnosis.

Edaravone attenuates sustained pial arteriolar vasoconstriction independently of endothelial function after unclamping of the abdominal aorta in rabbits.

BACKGROUND: Cerebral blood flow (CBF) has direct effects on neuronal function and neurocognitive disorders. Oxidative stress from abdominal aortic surgery is important in the pathophysiology of CBF impairment. We investigated the effect of edaravone on the pial arteriolar diameter changes induced by abdominal aortic surgery and the involvement of the endothelium in the changes. METHODS: The closed cranial window technique was used in rabbits to measure changes in pial arteriolar diameter after the unclamping of abdominal aortic cross-clamping with an intravenous free radical scavenger, edaravone (control group [n = 6], edaravone 10 µg/kg/min [n = 6], 100 µg/kg/min [n = 6]). Pial vasodilatory responses to topical application of acetylcholine (ACh) into the cranial window were investigated before abdominal aortic cross-clamping and after unclamping with intravenous administration of edaravone (control group [n = 6], edaravone 100 µg/kg/min [n = 6]). RESULTS: Aortic unclamping-induced vasoconstriction was significantly attenuated by continuous infusion of edaravone at 100 µg/kg/min. Topical ACh after unclamping did not produce any changes in pial arteriolar responses in comparison to before aortic cross-clamping in the control or edaravone groups. The changes in the response to topical ACh after unclamping in the saline and edaravone groups did not differ significantly. CONCLUSIONS: Free radicals during abdominal aortic surgery might have contracted cerebral blood vessels independently of endothelial function in rabbits. Suppression of free radicals attenuated the sustained pial arteriolar vasoconstriction after aortic unclamping. Thus, the free radical scavenger might have some brain protective effect that maintains CBF independently of endothelial function.

Comparative effects of cilostazol and aspirin on the impairment of endothelium-dependent cerebral vasodilation caused by acute cigarette smoking in rats.

We previously reported that acute cigarette smoking can cause a dysfunction of endothelium-dependent vasodilation in cerebral vessels, and that a reduction of oxidative stress by agents such as valsartan, fasudil, or apocynin prevented this impairment. Here, our aim was to investigate the comparative effects of two antiplatelet drugs used for stroke-prevention [a phosphodiesterase-3 inhibitor (cilostazol) and a cyclooxygenase inhibitor (aspirin)] on smoking-induced endothelial dysfunction in cerebral arterioles. In Sprague-Dawley rats, we used a closed cranial window preparation to measure the changes in pial vessel diameters induced by topical application of acetylcholine (ACh) following intraperitoneal injection of 0.5% carboxymethyl cellulose sodium salt (CMC; vehicle control for the antiplatelet drugs). After 1-min smoking (1 mg-nicotine cigarette), the arteriolar responses to ACh were reexamined. Finally, after intraperitoneal cilostazol or aspirin (each in 0.5% CMC) pretreatment, we reexamined the vasodilator responses to topical ACh (before and after cigarette smoking). Under control conditions, cerebral arterioles were dose-relatedly dilated by topical ACh (10(-6) and 10(-5 )M). One hour after 1-min smoking, 10(-5 )M ACh (a) constricted cerebral pial arterioles in the control group and in the aspirin-pretreatment group (responses not significantly different from each other), but (b) dilated cerebral pial arteries in the cilostazol pretreatment groups (responses significantly different from those obtained without cilostazol pretreatment). Thus, cilostazol (but not aspirin) may prevent the smoking-induced impairment of endothelium-dependent vasodilation in cerebral pial arterioles.

Cigarette Smoking Cessation Temporarily Enhances the Release of Phosphorylated-HSP27 from Human Platelets.

Objective Cigarette smoking is a risk factor for arteriopathy, including acute coronary syndrome, stroke and peripheral vascular disease. Thus, cessation is strongly recommended in order to reduce these risks. We recently demonstrated that smoking cessation causes temporary hyper-aggregability of human platelets. We previously showed that heat shock protein 27 (HSP27) is released from human platelets stimulated by collagen, accompanied by its phosphorylation. Accumulating evidence indicates potent roles of extracellular HSP27 as a modulator of inflammation. In the present study, using the stored samples obtained in the previous study, we investigated the effect of cigarette smoking cessation on the release of phosphorylated-HSP27 from collagen-activated human platelets (n=15 patients). Methods We enrolled patients who visited smoking cessation outpatient services between January 2012 and November 2014. Platelet-rich plasma, chronologically obtained before and after the cessation, was stimulated by collagen using a PA-200 aggregometer in the previous study. The levels of phosphorylated-HSP27 released from platelets were determined by an enzyme-linked immunosorbent assay. The phosphorylation of HSP27 in platelets was evaluated by a Western blot analysis. Results Cessation of cigarette smoking significantly upregulated the levels of collagen-stimulated release of phosphorylated-HSP27 at four and eight weeks after quitting smoking compared to before cessation. However, there was no significant difference between the levels before cessation and those at 12 weeks after cessation. The levels of phosphorylated-HSP27 stimulated by collagen in the platelets at four weeks after smoking cessation were remarkably enhanced compared to before cessation. Conclusion Cigarette smoking cessation temporarily enhances the collagen-stimulated release of phosphorylated-HSP27 from human platelets in the short term.

Smoking cessation affects human platelet activation induced by collagen.

It is firmly established that smoking is a risk factor of cardiovascular disease, stroke and peripheral vascular disease. Although smoking alters the hemostatic process, the influence of smoking on human platelet activation remains controversial. For patients undergoing surgery, cessation of smoking prior to the procedure is recommended as it increases the risk of postoperative morbidity or mortality. The presented study investigated the effects of smoking cessation on human platelet activation induced via collagen (n=19 patients). Blood samples were taken on four occasions: Before smoking cessation, and at 4, 8 and 12 weeks after smoking cessation. Platelet aggregation using citrated platelet-rich plasma (PRP) was monitored using a PA-200 aggregometer, which determined the size of platelet aggregates using laser scattering methods. A low dose of collagen (1 µg/ml) accelerated platelet aggregation at 4 or 8 weeks after smoking cessation when compared with results before cessation. After 12 weeks, levels of platelet aggregation induced by collagen were almost equal to those recorded prior to smoking cessation. The secretion levels of collagen-induced platelet-derived growth factor (PDGF)-AB at 4 or 8 weeks after smoking cessation were significantly higher than those before smoking was stopped. Furthermore, smoking cessation markedly strengthened the collagen-induced phosphorylation of p38 mitogen-activated protein (MAP) kinase after 4 weeks. The results of the current study indicated that smoking cessation causes temporary short-term human platelet hyper-activation. The further suggest that the incidence of complications due to human platelet hyper-reactivity may be lowered by considering the period of smoking abstinence.

The effects of transient cerebral ischemia on vasopressin-induced vasoconstriction in rabbit cerebral vessels.

BACKGROUND: Vasopressin is a drug of choice for use during cardiopulmonary resuscitation because several experimental studies have shown that it is better than epinephrine at increasing systemic perfusion pressure and improving cerebral perfusion pressure without increasing myocardial oxygen consumption. We used a pial window preparation to determine the effects of vasopressin when applied topically to pial vessels and whether any effects were altered after cerebral ischemia in rabbits (n = 27). METHODS: We first examined the effects of topical application of arginine-vasopressin (AVP) (10(-11) M, 10(-9) M, 10(-7) M, and 10(-5) M, sequentially). We then examined the effects of topical application of AVP (10(-9) M and 10(-7) M, sequentially) before and after a 5-min intervention consisting of cerebral ischemia produced by inflation of a neck tourniquet plus systemic hypotension or systemic hypotension alone. RESULTS: Pial arteriolar diameters were (a) dilated by 10(-11) M AVP [7% +/- 11% (P = 0.014 versus baseline)], but constricted by 10(-9) M, 10(-7) M, and 10(-5) M AVP [7% +/- 14%, 20% +/- 14%, and 16% +/- 16% (each P < 0.05), respectively], and (b) constricted before hypotension (7% +/- 10% at 10(-9) M, 20% +/- 15% at 10(-7) M) or ischemia (7% +/- 11% at 10(-9) M, 21% +/- 15% at 10(-7) M). However, after the 5-min of ischemia, the decrease in diameter induced by 10(-7) M AVP was significantly reduced but not by hypotension alone [hypotension control group: 7% +/- 10% at 10(-9) M, 19% +/- 14% at 10(-7) M; ischemia group: 5% +/- 11% at 10(-9) M, 10% +/- 13% at 10(-7) M (P = 0.35 versus hypotension control)]. CONCLUSIONS: Topical application of AVP (except at the lowest concentration used here) induced concentration-dependent vasoconstriction of pial arterioles in anesthetized rabbits. The vasoconstrictor effect of 10(-7) M AVP was reduced after transient (5-min) cerebral ischemia.

Rho-kinase inhibitor and nicotinamide adenine dinucleotide phosphate oxidase inhibitor prevent impairment of endothelium-dependent cerebral vasodilation by acute cigarette smoking in rats.

INTRODUCTION: We previously reported that acute cigarette smoking can cause a dysfunction of endothelium-dependent vasodilation in cerebral vessels, and that blocking the angiotensin II (Ang II) type 1 (AT1) receptor with valsartan prevented this impairment. Our aim was to investigate the effects of a Rho-kinase inhibitor (fasudil) and a Nicotinamide Adenine Dinucleotide PHosphate (NADPH) oxidase inhibitor (apocynin) on smoking-induced endothelial dysfunction in cerebral arterioles. METHOD: In Sprague-Dawley rats, we used a closed cranial window preparation to measure changes in pial vessel diameters following topical acetylcholine (ACh) before smoking. After one-minute smoking, we again examined the arteriolar responses to ACh. Finally, after intravenous fasudil or apocynin pre-treatment we re-examined the vasodilator responses to topical ACh (before and after cigarette smoking). RESULTS: Under control conditions, cerebral arterioles were dose-dependently dilated by topical ACh (10(-6) M and 10(-5) M). One hour after a one-minute smoking (1 mg-nicotine cigarette), 10(-5) M ACh constricted cerebral arterioles. However, one hour after a one-minute smoking, 10(-5) M ACh dilated cerebral pial arteries both in the fasudil pre-treatment and the apocynin pre-treatment groups, responses that were significantly different from those obtained without fasudil or apocynin pre-treatment. CONCLUSION: Thus, inhibition of Rho-kinase and NADPH oxidase activities may prevent the above smoking-induced impairment of endothelium-dependent vasodilation.

The comparative effects of intravenous nicardipine and prostaglandin E1 on the cerebral pial arteriolar constriction seen after unclamping of an aortic cross-clamp in rabbits.

BACKGROUND: The potent vasodilators nicardipine and prostaglandin E1 (PGE1) are useful for the treatment of systemic hypertension or pulmonary hypertension during aortic surgery. METHODS: We measured cerebral pial arteriolar diameters, using a rabbit closed cranial window preparation: before (baseline) and 15 min after the start of an IV infusion (preclamp) (0.9% saline [control group], nicardipine [at 0.1, 1.0, or 10 microg x kg(-1) x min(-1)], or PGE1 [at 0.1 or 1.0 microg x kg(-1) x min(-1)]), just after aortic clamping, 20 min after clamping, and at 0-60 min after unclamping. RESULTS: In the control group, a significant decrease in diameter persisted for at least 60 min after unclamping (maximum [at 60 min], -16% for large [> or =75 microm], and -27% for small [<75 microm] arterioles versus baseline). Although the aortic unclamping-induced vasoconstriction was unaffected under the smallest dose of nicardipine, it was significantly attenuated under larger doses in both large and small arterioles (residual vasoconstriction, -10% and -6% for large and -18% and -10% for small arterioles; at 60 min). The pial arteriolar constriction observed at 5 min or more after unclamping in the control group was not altered by PGE1 in either large or small arterioles. CONCLUSIONS: The larger doses of nicardipine, but neither dose of PGE1, attenuated aortic unclamping-induced sustained cerebral pial arteriolar constriction.

Angiotensin II type 1 (AT1)-receptor blocker prevents impairment of endothelium-dependent cerebral vasodilation by acute cigarette smoking in rats.

Our aim was to test for smoking-induced endothelial dysfunction in rat cerebral vessels, then to evaluate the effect of valsartan [angiotensin II type I (AT1)-receptor blocker] on that impairment. In pentobarbital-anesthetized, mechanically ventilated Sprague-Dawley rats, we used a cranial window preparation to measure changes in pial vessel diameters following topical applications of acetylcholine (Ach) (before and after smoking or intravenous nicotine infusion; n = 6 in each group), and adenosine (n = 6 for before and after smoking). Then, after intravenous valsartan pretreatment we reexamined the pial vasodilator response to topical Ach (before and after cigarette smoking). Under control conditions, cerebral arterioles were dilated by 6.9 +/- 4.2% and 13.6 +/- 4.8% by topical Ach (10(-6) M and 10(-5) M, respectively) and by 6.4 +/- 2.5% and 12.2 +/- 3.1% by topical adenosine (10(-5) M and 10(-4) M, respectively). One hour after a 1-min inhalation of mainstream smoke (1-mg nicotine cigarette), 10(-5) M Ach constricted cerebral arterioles (-4.4 +/- 4.1%), while 10(-4) M adenosine dilated them by 13.4 +/- 3.4%. One hour after a 1-min nicotine infusion (0.05 mg), 10(-5) M Ach dilated cerebral arterioles by 9.9 +/- 2.4%. Thus, vasodilator response to topical Ach was impaired after smoking, whereas that to adenosine was unaffected. However, the vasodilator response to Ach was unaffected by intravenous nicotine. Valsartan prevented smoking from impairing Ach-induced vasodilation. In conclusion, acute single-cigarette smoking causes a dysfunction of endothelium-dependent, but not endothelium-independent, vasodilation of rat cerebral vessels in vivo, and the effect was not mimicked by intravenous nicotine. AT1-receptor blockade prevented the above smoking-induced impairment of endothelium-dependent vasodilation.