Effects of pilocarpine hydrochloride and cevimeline on submandibular/sublingual salivation in rat xerostomia model produced by X-ray irradiation.
The present study was performed to assess the effects of pilocarpine hydrochloride ((3S,4R)-3-ethyl-dihydro-4-[(1-methyl-1H-imidazole-5-yl)methyl]-2(3H)-furanone monohydrochloride, CAS 54-71-7) and cevimeline ((+/-)-cis-2-methylspiro[1,3-oxathiolane-5,3'-quinuclidine] hydrochloride, hemihydrate, CAS 153504-70-2), muscarinic receptor agonists, on salivary secretion from the submandibular/sublingual (SM/SL) glands in normal rats and in rats with xerostomia induced by X-ray (15 Gy) irradiation. To clarify their pharmacological safety profiles, the two drugs were further compared with regard to subtype selectivity for muscarinic receptors (M1, M2, and M3) and central nervous, respiratory, and cardiovascular effects. Pilocarpine hydrochloride (0.1-0.8 mg/kg i.d.) and cevimeline (3-30 mg/kg i.d.) dose-dependently increased salivary flow rate and total salivary volume in a 120-min period from SM/SL glands in both normal and irradiated rats, the minimum effective doses for their sialagogic effects being 0.2 and 10 mg/kg, respectively. Both drugs also increased protein output from SM/SL glands to a degree that depended on the increase in salivary volume in normal and irradiated rats. In a binding study using radiolabeled antagonists, neither pilocarpine hydrochloride nor cevimeline displayed subtype selectivity for muscarinic receptors, indicating non-selective muscarinic agonism. Effects on the central nervous system (CNS) were assessed by monitoring changes in body temperature in conscious normal rats. Pilocarpine hydrochloride (0.4-4 mg/kg p.o.) had no effect on body temperature, but cevimeline (30 and 100 mg/kg p.o.) caused a significant hypothermia. In terms of respiratory and cardiovascular effects in anesthetized normal rats, there was no clear difference in safety margin between pilocarpine hydrochloride and cevimeline, both drugs inducing significant changes in respiratory rate, heart rate, and blood pressure at doses close to those inducing sialagogic effects. These results suggest that pilocarpine hydrochloride could be used as a sialagogic drug for postirradiation-induced xerostomia with fewer adverse effects on the CNS.
Omori
Yasuhiro
Y
Clinical Development, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan.
Asari
Tetsuya
T
Maruyama
Kazuyasu
K
Kusama
Hiroshi
H
Kojima
Masami
M
Shibata
Nobuo
N
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001831:Body Temperature / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects; D002490:Central Nervous System / Q000187:drug effects; D002746:Chlorpromazine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology*; D010862:Pilocarpine / Q000494:pharmacology*; D011812:Quinuclidines / Q000494:pharmacology*; D011833:Radiation Injuries, Experimental / Q000188:drug therapy / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism; D012137:Respiratory System / Q000187:drug effects; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D012472:Salivation / Q000187:drug effects*; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism*; D013876:Thiophenes; D014987:Xerostomia / Q000188:drug therapy* / Q000503:physiopathology
D014150:Antipsychotic Agents; D018721:Muscarinic Agonists; D011812:Quinuclidines; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic; D012471:Salivary Proteins and Peptides; D013876:Thiophenes; D010862:Pilocarpine; C059240:cevimeline; D002746:Chlorpromazine