Anatomic regions

Pharmacokinetic Model—A set of equations that can be used to describe the time course of a parent chemical or metabolite in an animal system. There are two types of pharmacokinetic models data-based and physiologically-based. A data-based model divides the animal system into a series of compartments which, in general, do not represent real, identifiable anatomic regions of the body whereby the physiologically-based model compartments represent real anatomic regions of the body. 

Anatomical Region Receptor Density (fmol/mg Tissue) ... 

Fig. 2 Diagrammatic sketch of the stomach and anatomical regions. (Modified from Ref. 5.)...

The availability of rodent models of nicotine physical dependence and abstinence has made it possible to identify several anatomical regions that play a critical role in these phenomena. In reviewing the evidence, the multidimensional nature of the nicotine withdrawal syndrome should be considered, raising the possibility that different withdrawal signs and symptoms might be attributable to events in different anatomical regions. Table 2 summarizes a number of representative studies. There is some overlap with Table 3 on neurochemical mechanisms, since many studies cited there are studies of regional neurochemistry. 

Table 2 Anatomical regions involved in nicotine withdrawal...

Anatomical region Withdrawal measure or neurochemical correlate Some representative references... 

It is worth noting that differences among membranes, such as the presence of different lipids, the amount of surface lipid, differences in size and shape of proteins, or physical features of bonding, may cause differences in permeability among membranes. These biochemical and biophysical differences are thought to be responsible for permeability differences in skin from different anatomical regions of the body. 

Few studies address the effects of anatomic region, age, gender, or race as they pertain to the friction coefficient. To date, no significant differences have been found with regard to gender8,22,24... 

Cua, A., Wilheim, K.P., and Maibach, H.I., Frictional properties of human skin relation to age, sex and anatomical region, stratum comeum hydration and transepidermal water loss, Br. J. Dermatol., 1990 123 473-479. 

Recently, Sedqi et al. [24] were able to clone a delta opioid receptor complementary DNA by expression of cDNA library from activated thymocytes in Cos 7 cells, whose amino acid sequence was similar to the neural counterpart. Interestingly, they also observed that transcripts for kappa and mu opioid receptors were not detected in thymocytes. Furthermore, Gave-riaux et al. [25] demonstrated transcripts for the delta opioid receptor in T-lymphocyte, B-lymphocyte, and monocyte cell lines, as well as in murine splenocytes. However, they observed that the kappa opioid receptor transcript was only found in B-cell lines. These studies may suggest a selective expression of the delta opioid receptor in specific cells and tissues of the immune system and suggests specialized functions in different anatomical regions. 

---