Doctor Specializes in Pot Research
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Concentrates on Physical Effects Doctor Specializes in Pot Research By Elaine King Times Medical Writer If you smoke a joint of marijuana and don't get high, don't be fooled into thinking that marijuana doesn't bother you. It does. Your pulse rate will speed up and your eyes will get bloodshot, even if you don't feel the much talked about high attributed to smoking marijuana. Those are things that a marijuana smoker can tell for himself. But there are also some less obvious physical effects that scientists have recently discovered. Dr. Joseph Manno of Shreveport outlined some of the things he has learned about marijuana's effects on users' bodies in his extensive research. He and his wife, Dr. Barbara Manno, have continued researching marijuana and its effects on the body for several years. Both are associate professors of pharmacology and therapeutics at Louisiana State University School of Medicine in Shreveport and she is a phar-macologist in medical research at the Veterans Administration. For instance, he explained, by injec-ting THC (the ingredient in marijuana analogous to alcohol in liquor) into an isolated heart, the Mannos discovered that the blood vessels to the heart con-stricted and the heart beat with substan-tially less force than before. The amount of THC (tetrahydrocan-nibinol) used in the experiment was close to the amount found in the blood after smoking marijuana. In other tests that amount was increased to simulate the higher concentrations of THC in the blood of regular users since THC accumulates in the blood stream, he explained. In a healthy person, those effects probably wouldn't cause any physical problems, Dr. Manno said. Could Be Dangerous But for anyone whose "heart is not a completely efficient pump" it could be dangerous, he said. Research with animals to determine effects of marijuana on the heart, was corroborated, Dr. Manno noted, by fin-dings of a California researcher who used I heart patients in research. In the California research, conducted under controlled conditions, the heart I patients would begin exercising and con-tinue until their chest pains began. If it took five minutes for the pains to begin after exercise started, it would take only half as long for the pain to develop [after the person smoked marijuana, according to Dr. Manno. In Shreveport none of the marijuana research has included people, which made corroboration of some of the Mannos other findings difficult, he said. "You can't pull people off the streets" for research tests, he commented. But now, coupling his own results with the'findings from the California research, Dr. Manno can caution that if a marijuana smoker, who suddenly stands up after being seated or reclined, faints it is no coincidence. And it's no coincidence if after smoking marijuana chest pains begin. It's likely a heart problem aggravated by the marijuana's effects, he said. The Mannos are among a group of about half a dozen scientists in the United States whose marijuana research concen-trates on the physical effects. Most of the researchers have delved i n s t e a d into the psychological implications of smoking marijuana, he said. Smoker May Faint One of the reasons that a marijuana smoker may faint or get weak if he stands after smoking is because the blood vessels don't constrict as they normally do to keep gravity from pulling the blood down-ward when a person stands, Dr. Manno theorized. If that's true, then marijuana also has a dilating effect on areas other than the eyes, in direct contrast to the constriction of the heart blood vessels, he said. That could be caused by different effects along the central nervous system or it could affect parts of the body differen-tly. "Why I have no idea," he readily admits. That's what the on-going research is all about. To find out the unknown about what marijuana does to the body, and why. The latest research underway will take months to conduct and is aimed at finding out if marijuana affects the central ner-vous system directly. Working with Dr. Manno on the project, which involves rats, is Elizabeth Loftus, who is working on her Ph.D. In the past, the Mannos' research with animals has yielded important results that corroborated theories about marijuana and its physical effects. For instance in early research the Mannos were able to prove the in-creased pulse rate by giving animals THC in small doses that equal the blood level amount. Previous researchers had found a decreased pulse rate in animals injected with THC. But those results came when high doses were injected into anethesized animals, Dr. Manno said. The Mannos work proved the in-creased heart rate was caused by THC. Research is centering on THC metabolites, the altered form of THC after it is processed through the body. If THC is admijustered into test animals, Dr. Manno noted, it takes about 90 minutes for the increased pulse rate to begin. But if a metabolite is injected, the heart rate picks up immediately, he said. The Manno research into what marijuana can do physically to a smoker is still continuing in an effort to find out more about the controversial drug. Where is the research leading? Eventually, said Dr. Manno, he would like to work with coroner cases to establish how often THC is found in the bloodstream of persons involved in automobile fatalities. That's much the same way that alcohol was finally pinpointed as a major factor in wrecks, he noted. Checking out some of the equipment used to test marijuana's effects on rats ris. Dr. Joseph Manno, who has been conducting research on the physical effects of marijuana. (Times Photo by John Denison)
|Title||Doctor Specializes in Pot Research|
King, Elaine T.
Denison, John L.
Manno, Joseph E.
Louisiana State University School of Medicine (Shreveport, La.)
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|Source||Louisiana State University Health Sciences Center Shreveport Medical Library (http://lib.sh.lsuhsc.edu)|
|Coverage-Spatial||Shreveport (Caddo, La.)|
|Rights||Physical rights are retained by Louisiana State University Health Sciences Center Shreveport. Copyright is retained in accordance with U.S. copyright laws.|