1173 



Luduena, F. P., and Theodore G. Brown, Jr. 1952. 



Mytolon and related compounds as antagonists of acetylcholine on the heart 

 of Venus mercenaria. J. Pharmacol. Exper . Therap. 105(2) : 232-239. 



The acetylcholine (ACh) blocking effect of various ganglionic and 

 neuromuscular blocking agents was determined on isolated hearts of Venus 

 mercenaria. No blocking activity at concentrations as great as 1:10,000 

 was shown by d-tubocurarine, decamethonium and dihydro-beta-erythroidine. 

 Tetraethylammonium bromide (TEA) and various benzoquinone derivatives 

 reduced the inhibitory effect of ACh on Venus heart, and at higher 

 concentrations blocked the inhibitory effect. WIN 2747, Mytolon, /J,5-bis 

 (diethylaminopropylamino) -benzoquinone benzochloridey', the most potent 

 compound tested, was about 1,000 times as active as TEA. No correlation 

 was found between ACh blocking activity on Venus heart and ganglionic 

 blocking, curarimimetic or anticholinesterase activities. Positive 

 correlation between ganglionic blocking activity in mammals and ACh 

 antagonism on Venus heart would have made it possible to use Venus heart 

 for screening ganglionic blocking agents. The high sensitivity to Mytolon 

 might have practical value as the basis of a bioassay method for quantitative 

 determination of this drug in biological material. - modified authors' summary 

 - J.L.M. 



1174 



Lutz, Richard A. 1978. 



The bivalve "larval ligament" as an" exclusively post-larval feature. Natl. 

 Shellf. Assn., 70th Joint Ann. SINA-NSA Conv. & Meeting, 18-22 June 1978, 

 Abstracts: (page not numbered). 



Morphological structures of bivalves formerly referred to as "larval 

 ligaments" are postlarval features. Presence of a ligament pit on the 

 ventral surface of the hinge apparatus of small planktonic bivalves shows 

 that attachment or byssal secretion has occurred, and the size and 

 development of this structure helps to determine the extent to which the 

 process has proceeded. If secretion of the dissoconch shell marks the end 

 of metamorphosis, the prodissoconch-dissoconch boundary is useful in 

 distinguishing true juveniles from "metamorphosing" postlarvae. - J.L.M. 



1175 



Lutz, Richard A., and David Jablonski. 1978. 



Micro- and ultramorphology of larval bivalve shells: Ecological, 

 paleoecological, and paleoclimatic applications. Natl. Shellf. Assn., 70th 

 Joint Ann. SINA-NSA Conv. & Meeting, 18-22 June 1978, Abstracts: (page not 

 numbered) . 



Identification of larval bivalve shells is difficult or impossible with 

 routine microscopic procedures. A method is suggested whereby individual 

 larval or early postlarval material of certain closely related species may 

 be differentiated through routine examination of hinge apparatus. Species 

 are not mentioned, but the methods described might be applicable to 

 Mercenaria mercenaria. - J.L.M. 



1176 



Lutz, Richard A., and Donald C. Rhoads. 1977. 



Anaerobiosis and a theory of growth line formation. Science 198(4323): 

 1222-1227. 



Although a 1/1 correspondence has not been established, deposition of 

 increments in bivalves correlates well with shell valve movements. Valves 

 of many species usually close at low tide and open at high tide, and the 

 number of increments and number of tides are highly and positively 

 correlated. This rhythmicity usually is most pronounced in intertidal 

 bivalves, but Mercenaria mercenaria in the subtidal zone shows pronounced 



329 



