For 30 years (1956–1986), he was a tenured professor and chairman of the Department of Pharmacology and Experimental Therapeutics at Loyola University of Chicago Medical Center, and director of its Institute for Mind, Drugs and Behavior.
He is recognized for his experimental research, nearly all of which focused on the cholinergic system, both central and peripheral, and its autonomic and mental functions including its role in controlling various human and animal behaviors.
His studies in biological and medical sciences at the Józef Piłsudski University of Warsaw were interrupted by several anti-Semitic outbursts and by World War II.
He became a fellow at Sterling Winthrop Research Institute, Rensselaer, New York from 1953 to 1956, where he was a member of a team that developed Ambenonium (Mytelase), a drug still used in the treatment of myasthenia gravis, and the vasodilator amotriphene (Myordil).
In 1956, Karczmar moved to Loyola University Medical Center in Maywood, Illinois, where he served from 1956 to 1986 as professor and chairman of the Department of Pharmacology and Experimental Therapeutics, and as the senior director of the Institute for Mind, Drugs and Behavior from 1964 to 1986; he was also associate dean for research and graduate education from 1981 to 1986.
His text, Exploring the Vertebrate Central Cholinergic Nervous System (Springer, New York, 2007) reviews the past and the present status of central cholinergicity, its physiology, pharmacology, and biochemistry, its ontogeny and phylogenesis, and its role in functions, behaviors (including cognition), the "self" and such disease states as schizophrenia and Alzheimer's disease; this text also describes his own studies of these subjects.
This research led Karczmar to conceptualize the pre-neurogenetic appearance of components of the cholinergic system, their non-parallel ontogenesis and its significance, and their omni-existent phylogenesis which is independent of the presence of innervation or motility.
[11] Since the 1960s, Karczmar contributed to establishing the pre-eminent role of the central cholinergic system in functions such as respiration, behaviors such as aggression,[12] perceptions such as nociception,[13] learning,[14] addiction,[15] obsession and fixation, and sexual and motor activity,[16] and in phenomena such as seizures,[17] EEG rhythms, paradoxical sleep, and behavioral and EEG alerting;[18] and he and his associates provided early neurochemical evidence for the interaction between the cholinergic and other transmitter systems.
[21] From the 1970s onwards, Karczmar explored the "self" (the "I", the self-awareness, the self-consciousness[22] ); he traced the concept of the body-mind relation to the earliest history of mankind, millennia before the advent of Descartes' dualism.
He speculated that with the future success of Einstein's quest for the single equation for all the forces of the universe, the nature of "I" will become explainable, perhaps via multidimensional string theory.