Cardiovascular uses of cannabinoid compounds

Hemorrhagic shock and in other conditions associated with excessive vasoconstriction, such as hypertension, peripheral vascular disease, cirrhosis of the liver, or certain forms of angina pectoris can be treated by using agonists of CB1 receptors as well as other cannabinoid receptors. In addition, it has been determined that in septic shock and cirrhosis of the liver when hypotension is due to activation of macrophages by bacterial endotoxin, the use of a drug that selectively blocks CB1 receptors or other cannabinoid receptors may be of therapeutic value by preventing or attenuating the endotoxin-induced hypotension.

DESCRIPTION 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to the cardiovascular effects of cannabinoid 
compounds, i.e. naturally occurring as well as synthetic substances that 
bind with high affinity to cannabinoid receptors in the brain and in 
peripheral tissues of mammals, including man. 
2. Description of the Prior Art 
Naturally occurring cannabinoids may be divided into two categories, 
plant-derived and endogenous. Plant-derived cannabinoids are known to 
elicit dramatic psychobehavioral effects, exemplified by the well-known 
.DELTA..sup.9 -tetrahydrocannabinol (THC), the psychotropic principle in 
marijuana. They are also known to have complex cardiovascular effects, a 
prominent component of which is hypotension (Vollmer et al. J. Pharm. 
Pharmacol. 1974, 26:186-198) Endogenous cannabinoids (endocannabinoids) 
are a class of lipid-like molecules that share receptor binding sites with 
plant-derived cannabinoids and mimic many of their neurobehavioral effects 
(Mechoulam et al. Adv. Exp. Bio. Med. 1996, 402:95-101.) Two 
endocannabinoids have been characterized in some detail: arachidonyl 
ethanolamide (anandamide) (Devane et al. Science 1992, 258:1946-1949; 
Felder et al. Proc. Natl. Acad. Sci. USA. 1993, 90:7656-7660) and 
2-arachidonyl glyceride (2-AG) (Mechoulam et al. Biochem. Pharmacol 1995, 
50:83-90). Like plant-derived cannabinoids, both anandamine and 2-AG are 
capable of eliciting hypotension (Varga et al. FASEB J. 1998, 
12:1035-1044; Varga et al. Eur. J. Pharmacol. 1995, 278:279-283; Stein et 
al. Br. J. Pharmacol. 1996, 119:107-114; Varga et al. Hypertension 1996, 
28:682-688; Lake et al. Hypertension 1997, 29:1204-1210; Calignano et al. 
Eur. J. Pharmacol. 1997, 337: R1-R2). In addition, various cannabinoid 
compounds have been produced synthetically. 
Cannabanoids exert their effects by binding to specific receptors located 
in the cell membrane. To date, two types of high-affinity cannabinoid 
receptors have been identified by molecular cloning: 1) CB1 receptors, 
present mostly in brain (Devane et al. Mol. Pharmacol. 1988, 34:605-613; 
Matsuda et al. Nature 1990, 346:561-564) but also in some peripheral 
tissues (Shire et al. J. Biol. Chem. 1995, 270:3726-3731; Ishac et al. Br. 
J. Pharmacol. 1996, 118:2023-2028), and 2) CB2 receptors, present on 
macrophages in the spleen (Munro et al. Nature 1993, 365:61-65). 
The physiologic roles of endogenous cannabinoids and the pathways by which 
those roles are implemented are the subject of intense investigation. The 
observation that cannabinoids induce hypotension suggests a potential role 
for these substances in cardiovascular function. The results of a recent 
study by Lake et al.(J. Pharmacol. Exp. Ther. 1997, 281:1030-1037) lends 
credence to this idea. The study suggested that, when injected into 
anesthetized or conscious rats, anandamide and other cannabinoid 
substances cause profound hypotension mediated by peripheral CB1 receptors 
present in the heart and vasculature. However, further direct links 
between the endogenous cannabinoids and cardiovascular functions have been 
wanting. Results which are described herein supply that link and form the 
basis for the invention of a method described below whereby cannabinoid 
compounds can be used to ameliorate pathological conditions associated 
with hemodynamic abnormalities. 
SUMMARY OF THE INVENTION 
This invention provides a method for the treatment of pathological states 
related to hemodynamic abnormalities such as hypotension and hypertension 
using cannabinoids or cannabinoid-related compounds. The impetus for the 
invention depended directly on the development of a novel concept of the 
role of endogenous cannabinoids and their receptors in the control of 
cardiovascular functions, such as blood pressure, and thus the implication 
of their involvement in various pathological states associated with 
hypotension and hypertension. 
We have recently reported two related lines of investigation, both of which 
demonstrate that endocannabinoids and their receptors may be directly 
involved in the control of cardiovascular functions, such as blood 
pressure. The first study (Wagner et al. Nature 1997, 390:518-521) showed 
that, in anesthesized rats, hypotension caused by hemorrhagic shock was 
accompanied by the production of the endogenous cannabanoid anandamide by 
circulating macrophages. When macrophages were isolated from animals in 
hemorrhagic shock and administered to normal control rats, hypotension was 
elicited in the recipient rats. In addition, the selective CB1 receptor 
antagonist SR141716A, when administered systemically to animals in 
hemorrhagic shock, caused a marked and prolonged increase in blood 
pressure. However, when SR141716A was administered centrally (i.e. 
directly into the brain, thus not reaching peripheral blood vessels) no 
such effect was observed. These results taken together suggest that the 
activation of peripheral (vascular) CB1 receptors contributes to 
hemorrhagic shock, and that anandamide produced by macrophages may be a 
mediator of this effect. The observed results were found to be independent 
of changes in nitrous oxide synthase (NOS) activity and circulating levels 
of nitrosothiols and thus may not be explained by mechanisms related to 
either of those substances. Significantly, pretreatment of the rats with 
anandamide-like cannabinoid agonists prolonged their survival, whereas 
pretreatment with SR141716A shortened survival. This suggests that the 
activation of CB1 receptors is beneficial for survival in hemorrhagic 
shock, probably because the attendant hypotension counters the excessive 
compensatory vasoconstriction that occurs following hemorrhage. Therefore, 
we propose that the use of CB1 receptor agonists may be of value in the 
treatment of hemorrhagic shock and in other conditions associated with 
excessive vasoconstriction, such as hypertension, peripheral vascular 
disease or certain forms of angina pectoris. 
Our second study (Varga et al. FASEB J. 1998, 12:1035-1044) was directed 
toward elucidation of the mechanism of hypotension induced by endotoxic 
(septic) shock. Endotoxic shock is a potentially lethal failure of 
multiple organs that is initiated by lipopolysaccharide (LPS or 
`endotoxin`) present in the outer membrane of gram-negative bacteria. The 
primary cellular targets of LPS are macrophages, which are activated by 
LPS to generate various cytokines. Although some symptoms of septic shock 
have been attributed to the LPS-induced release of cytokines from 
circulating macrophages (Wright et al. Science 1990, 249:1431-1433; 
Dentener et al. J. Immunol. 150:2885-2891; Sherry and Cerami J. Cell. 
Biol. 1988, 107:1269-1277), pharmacological antagonism of cytokine effects 
fail to provide protection from the hypotension of septic shock (Stone 
Science 1994, 264:365-367; Nantason et al. Ann. Int. Med. 120:771-783). 
Some other mechanism must be responsible. Our study showed that 
hypotension and tachycardia develop in normal rats injected with bacterial 
endotoxin or with monocytes or blood platelets from another rat that had 
been treated with endotoxin. In both cases, the hypotension but not the 
tachycardia could be prevented by pretreatment of the recipient rats with 
the CB1 receptor antagonist SR141716A. Further experiments showed that 
when macrophages were isolated from normal rat blood and treated in vitro 
with LPS, the presence of anandamide could be documented by gas 
chromatography/mass spectrometry, whereas in LPS-treated platelets, the 
generation of 2-AG could be demonstrated. These findings indicate that 
macrophages and platelets generate different endogenous cannabanoids 
(anandamide and 2-AG, respectively) in response to stimulation by LPS and 
that both anandamide and 2-AG may be mediators of endotoxin-induced 
hypotension via activation of vascular CB1 receptors. Based on these 
findings, we propose that in septic shock and related pathological 
conditions, the use of a drug that selectively blocks CB1 receptors can be 
of therapeutic value by preventing or attenuating the endotoxin-induced 
hypotension. 
Still more recent findings indicate that previously unknown 
SR141716A-sensitive receptors other than CB1 (`anandamine receptors`) may 
be involved in endotoxic shock. We therefore propose that, in the 
treatment of septic shock and related pathological conditions, drugs which 
block this new class of receptor will also be of great utility.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
Experiments outlined below show that the use of a drug that selectively 
blocks CB1 receptors will be of therapeutic value by preventing or 
attenuating endotoxin-induced hypotension. The related pathological states 
are septic shock and cirrhosis of the liver. Both of these conditions are 
known to be associated with elevated blood levels of endotoxin as well as 
hypotension. In these experiments, monocyte/platelet preparations were 
obtained from 18 patients with septic shock, and equal aliquots of the 
isolated cells were infused into a pair of anesthesized Sprague-Dawley 
rats instrumented to measure blood pressure and heart rate. One rat 
received 3 mg/kg SR141716A intravenously while the other rat received 
vehicle pretreatment. Mean arterial pressure (MAP) and heart rate were 
monitored for 2 hours. Infusion of monocytes/platelets into 
vehicle-pretreated rats caused a sustained reduction in blood pressure 
(max: -23.+-.3 mm Hg) and an increase in heart rate, whereas the same 
infusion into SR141716A-pretreated rats caused only a negligible change in 
blood pressure (-4.+-.2 mmHg) and an increase in heart rate similar to 
that in controls (FIG. 1). Monocytes/platelets isolated from healthy 
humans had no effect on blood pressure or heart rate. 
Similar observations were made using monocytes/platelets from 9 patients 
with chronic liver cirrhosis, a disease associated with elevated plasma 
levels of endotoxin and severe hypotension. Monocytes/platelets from 
cirrhotic patients elicited hypotension (max: -38.+-.10 mmHg) and 
tachycardia in vehicle-pretreated rats, and no significant hypotension but 
similar tachycardia in SR141716A-pretreated rats (FIG. 2). Again, 
monocytes and platelets from healthy humans had no effect on blood 
pressure or heart rate. These observations suggest that 
monocytes/platelets in patients with septic shock or in those suffering 
from chronic liver cirrhosis elicit hypotension via the activation of a 
SR141716A-sensitive receptor (receptor inhibited by SR141716A), whereas 
the tachycardia effect of these cells does not involve a similar 
mechanism. 
The evidence for a role of CB1 receptors in the above hypotensive 
conditions is based on the ability of the selective CB1 antagonist, 
SR141716A, to inhibit or reverse the hypotension. However, additional 
observations reported herein indicate that SR141716A may also inhibit a 
unique receptor distinct from the CB1 receptor. Such receptors, rather 
than the classical CB1 receptors, may mediate endotoxin-induced 
hypotension and may be targets for the treatment of endotoxin-related 
hypotension by receptor antagonists. 
These results suggest the general applicability of using ligands (i.e., 
agonists and antagonists) of cannabinoid receptors or cannabinoid-like 
receptors (i.e., receptors other than CB1) to treat pathological states of 
hypotension or hypertension in patients, including humans and animals. 
Sufficient quantities of these ligands should be supplied to the patients 
by appropriate delivery routes (i.e., i.v., i.p., oral, sublingual, 
subcutaneous, etc.) to either counteract the hypotension or hypertension 
pathology. 
MATERIALS AND METHODS 
Preparation of Rat Isolated, Buffer-Perfused Mesenteric Arterial Bed 
Male Sprague-Dawley rats weighing 300-350 g were anesthetized with ether. 
Following laparotomy, a second order branch of the superior mesenteric 
artery was cannulated using a PE60 polyethylene cannula. The mesenterium 
was then isolated following an established procedure, separated from the 
intestines and placed in a water-jacketed perfusion chamber maintained at 
37.degree. C. The preparation was perfused at a rate of 2 mL/min with 
Krebs-Henseleit solution (composition in mmol/L: NaCI 118, KCl 4.7, 
KH.sub.2 PO.sub.4 1.2, MgSO.sub.4 0.6, CaCI.sub.2 2.5. NaHCO.sub.3 25, 
glucose 11.7, pH 7.4) pregassed with 95% O.sub.2 /5% CO.sub.2, using a 
peristaltic pump (Rainin). Perfusion pressure was monitored via a T-tube 
inserted between the pump and the inflow cannula, and connected to a 
pressure transducer (Abbott, North Chicago, Ill.) and physiograph 
(Astromed, Cortland, N.Y.). After an equilibration period of 30 minutes, 
the perfusion pressure, which was usually 30-40 mmHg at this perfusion 
rate, was then raised to 80-100 mmHg by the inclusion of phenylephrine (15 
.mu.mol/L) in the perfusion medium. Once the perfusion pressure had 
stabilized, endothelium-dependent and independent vasodilator responses 
were tested by bolus intra-arterial injections of acetylcholine and sodium 
nitroprusside, respectively. The magnitude of vasodilation was expressed 
as percent relaxation, 100% being equal to the phenylephrine-induced 
contractile response. Unless indicated otherwise, drugs were injected as a 
bolus close to the artery, in a volume of 100 .mu.L over a period of 5 
seconds. In some experiments, rats received an i.p. injection of 15 mg/kg 
Escherichia coli lipopolysaccharide (LPS) two hours prior to removal of 
the mesenteric bed for the in vitro study. 
Endothelial Denudation 
To achieve endothelial denudation, the preparation was perfused with 
distilled water for 3 to 6 minutes or with 0.3% deoxycholate in 
Krebs-Henseleit buffer for 20-30 seconds. In both cases, phenylephrine was 
omitted from the medium during these perfusions, and was reintroduced once 
perfusion pressure became stable. Functional denudation was considered to 
be achieved when the maximal dilator response to acetylcholine was reduced 
to &lt;20% of control or converted to a pressor response, while the maximal 
dilator response to sodium nitroprusside remained unchanged. Only those 
preparations that met these criteria were used for further testing. 
Despite carefully controlled experimental conditions, the time of 
distilled water or detergent perfusion required for denudation remained 
variable, and the window between incomplete denudation and complete loss 
of vascular reactivity was found to be narrow. As a result, effective 
denudation was achieved in less than 20% of the preparations. 
Chemicals 
SR1 41716A 
(N-piperidin-1-yl!-5-4-chlorophenyl!-1-1,2-dichlorophenyl!-4-methyl-1Hp 
yrazole-3-carboxamide HCl) was a gift from Sanofi Co. (Montpellier, 
France); WIN 
55212-2(R!-+!-2,3-dihydro-5-methyl-3-{4-morpholinyl!methyl}pyrrolol1, 
2,3-de!1,4-benzoxazin-6-yl!-1naphthalenyl)methanone mesylate), 
R(+)-methanandamide, and N.sup.G -Nitro-L-arginine methyl ester 
hydrochloride (L-NAME) were from RBI (Natick, Mass.); THC (.DELTA..sup.9 
-tetrahydrocannabinol) and anandamide (arachidonyl ethanolamide) were 
kindly provided by Dr. Billy R. Martin, HU-210 (-!-11-OH-.DELTA..sup.9 
-THC) was a gift from Dr. Raphael Mechoulam, 2-arachidonyl glyceride was 
from Deva Biotech (Hatboro, Pa.). Acetyl-choline, sodium nitroprusside, 
phenylephrine, arachidonic acid, indomethacin, ionomycin, E. coli 
lipopolysaccharide (0127:B8) and urethane were from Sigma Chemical Co. 
(St. Louis, Mo.). SR141716A, THC, anandamide and HU-210 were dissolved in 
1:1:18 emulphor:ethanol:saline. WIN 55212-2 was dissolved in 1:1:18 
emulphor:DMSO:saline. Emulphor is a polyoxyethylated vegetable oil. 
Statistical analysis 
For comparing agonist effects tested in the same preparations in the 
absence and in the presence of an antagonist, the paired t test was used. 
For determining agonist ED.sub.50 values from graded dose-response curves, 
the statistical package of Tallarida was used. 
Results 
Endotoxin-induced hypotension is due to dilation of the arterioles in 
various organs, most prominently in the mesenterium that provides the 
blood supply to the guts. In an isolated, buffer-perfused rat mesenteric 
vascular bed preparation we found that anandamide elicits pronounced, 
dose-dependent vasodilation, which is inhibited by low concentrations of 
SR141716A (FIG. 3). Similar vasodilation was observed with 
meth-anandamide, a metabolically stable analog of anandamide. However, 
plant-derived and synthetic cannabinoids, which are known to potently bind 
to and activate CB1 cannabinoid receptors, had no vasodilator effect in 
this preparation (FIG. 4). This suggests that, at least in this vascular 
bed, anandamide causes dilation by a receptor distinct from CB1 receptors, 
but which is nevertheless sensitive to blockade by SR141716A. 
At a concentration of 0.5 .mu.mol/L, SR141716A significantly inhibited the 
dilator effect of anandamide to an extent which is comparable to its known 
antagonism of CB1 receptor-mediated effects (Rinaldi-Carmona et al. 1994, 
350:240-244). However, when the concentration of SR141716A was increased 
10-fold to 5 .mu.mol/L, the degree of inhibition increased only twofold, 
suggesting that additional, SR141716A-insensitive mechanisms also 
contribute to the vasodilator effect of anandamide (FIG. 3). 
This was supported by results obtained in additional experiments. Since 
anandamide may act on the endothelium or the vascular smooth muscle, or 
both, we tested the effects of anandamide in endothelium denuded 
preparations. In these preparations, anandamide retained its vasodilator 
action, although the effect was modestly but significantly reduced (FIG. 
5). A striking difference between the results obtained with intact versus 
denuded preparations was, however, that the effect of anandamide after 
denudation was no longer influenced by SR141716A: the dilator response to 
144 nmol of anandamide was 37.+-.5% in the absence and 38.+-.6% in the 
presence of 5 .mu.mol/L SR141716A (FIG. 5). These findings suggest that 
although anandamide is capable of causing vasodilation by a direct effect 
on smooth muscle, this effect is not mediated by an SR141716A-sensitive 
receptor. 
This possibility is further supported by our findings in genetically 
altered `knock-out` mice, which are deficient in CB1 receptors due to 
selective disruption of both alleles of the gene encoding this receptor 
(-/- mice). In the genetically matched controls homozygous for normal CB1 
receptors (+/+ mice), anandamide as well as plant-derived (.DELTA..sup.9 
-THC) and synthetic cannabinoids (HU-210, WIN 55212-2) cause pronounced 
hypotension (FIG. 6, filled circles), whereas in the -/- knockout mice 
none of the 4 agonists causes any hypotension (FIG. 6, open circles), 
which confirms the role of CB1 receptors in these effects. However, low 
doses of LPS (0.1-1 mg/kg i.p.) still cause prolonged hypotension in the 
-/- mice,and this effect can be prevented by pretreatment of the animals 
with 3 mg/kg SR141716A (FIG. 7). These observations suggest that the 
LPS-induced hypotension is mediated by an SR141716A-sensitive receptor 
distinct from the CB1 receptor, and possibly similar to the receptor 
mediating the mesenteric vasodilator effect of anandamide. Based on these 
findings, we propose that in septic shock, the use of a drug that 
selectively blocks CB1-like receptors (e.g., an anandamide receptor) will 
be effective in preventing or attenuating endoxotin-induced hypotension. 
In a preferred embodiment of this invention, the CB1 receptor antagonist 
SR141716A will be administered to patients suffering from severe cirrhosis 
for reversing the associated hemodynamic abnormality of hypotension. 
Cirrhosis affects 3.6 per 1000 adults in North America and causes over 
32,000 deaths and 20 million days of work loss annually. Much of this 
morbidity and mortality is due to the hemodynamic consequences of 
cirrhosis on portal and systemic circulation. The principal effect of 
cirrhosis on portal circulation is the development of portal hypertension. 
Portal hypertension has two components. First, it is initiated by an 
increase in outflow resistance through the portal system by distortion of 
the sinusoidal circulatory bed by scar tissue in cirrhosis. Second, and 
even more importantly, cirrhosis is associated with mesenteric ateriolar 
vasodilation which increases portal inflow. Portal pressure, the product 
of portal flow and outflow resistance, thus rises dramatically in patients 
with cirrhosis. The primary consequence of portal hypertension is the 
development of varices which can bleed; this causes a third of all deaths 
related to cirrhosis. While several pharmacological agents have been used 
to increase mesenteric arterial resistance in order to decrease portal 
flow and thus treat portal hypertension, they have met with only mixed 
success. In systemic circulation, the principal effect of cirrhosis is one 
of progressive vasodilation. This decreases the effective circulating 
volume of blood and activates Na-retentive mechanisms which lead to Na 
(sodium) and water retention and ascites, the most common complication of 
cirrhosis. As cirrhosis progresses, the vasodilated state worsens with 
decreasing mean artierial pressure, increased cardiac output and marked Na 
retention and eventually renal failure and death. 
It is therefore apparent that a vasodilatory state plays a key role in the 
pathogenesis of the two principal causes of morbidity and mortality in 
cirrhosis. Although a number of mediators have been implicated, no single 
agent has been clearly shown to be primarily responsible for the 
vasodilatory state. Moreover, antagonists to these agents have not 
successfully reversed the hemodynamic abnormalities in cirrhotic 
individuals. In addition, numerous studies have documented that endotoxin 
levels in the systemic as well as the portal circulation are increased in 
patients with cirrhosis compared to those with milder degrees of other 
liver diseases or healthy individuals (Lin et al. J. Hepatol. 1995, 
22:165-172). It is also well-established that the endotoxin levels are 
higher in those with more advanced cirrhosis who also have greater degrees 
of systemic and splanchic vasodilation, larger varices, greater ascites 
and poorer liver function (Chan et al. Scand. J. Gas. 1997, 32:942-946). 
It has been proposed that increased endotoxin levels increase nitric oxide 
(NO) production by increasing NO synthase (NOS) activity. However, 
experimental studies in animal models indicate that NOS activity is not 
increased in those with cirrhosis. It is therefore apparent that if 
elevated endotoxin levels and hemodynamic changes in patients with 
advanced cirrhosis are causally related, this in not via NO related 
hypotension. 
Based on our investigations, we conclude that the vasodilation in patients 
with cirrhosis is due in large measure to the production of cannabanoids 
by platelets/macrophages and that the vasodilated state can be reversed by 
an antagonist for a cannabinoid receptor (CB1 and CB1-like receptors being 
collectively referred to herein as canabinoid receptors). In particular, 
good results can be obtained with the CB1 receptor antagonist, SR141716A, 
which is available from Sanofi, Inc. The antagonist can be administered by 
a variety of different routes. The preferred delivery route is oral. The 
dose will depend on a number of factors including the age, gender, and 
previous medical history of the patient. It is expected that doses of 
0.5-2 mg/kg will have beneficial effects; however, selection of the dose 
can vary widely. In the clinical setting with human subjects, we suggest 
measuring the effects of SR141716A on pulse rate, blood pressure, portal 
venous flow, mesenteric arteriolar resistance, hepatic arterial flow, 
hepatic blood flow, and portal venous pressure. For example, patient 
response to the drug could be monitored by measurement of blood pressure 
at regular (eg. 10 minute) intervals. 
While the experiments above show the effects of the CB1 receptor antagonist 
SR141716A, it will be clear to one of skill in the art that a wide variety 
of other CB1 receptor antagonists (or antagonists of CB1-like receptors) 
could be used in the practice of this invention because the evidence 
presented indicates that the activation of CB1-like receptors mediates the 
hypotension of septic shock, and reversing hypotension is a primary goal 
of treatment. There are a number of well known antagonists for use in the 
practice of this invention (e.g. LY320135). Other examples of CB1 receptor 
antagonists can be found in U.S. Pat. No. 5,596,106 and U.S. Pat. No. 
5,747,524, both of which are herein incorporated by reference. 
In similar fashion, the agonists of CB1 receptors or CB1-like receptors 
could be used to treat conditions associated with excessive 
vasoconstriction, such as hypertension, peripheral vascular disease or 
angina pectoris. As cited previously (Lake et al.), CB1 agonists are known 
to lower blood pressure. However, CB1 agonists also elicit potent 
neurobehavioral (`marijuana-like`) effects by activating CB1 receptors in 
the brain (Compton et al., J. Pharmacol. Exp. Ther. 1996, 277:586-594), 
which limits their clinical usefulness. This problem could be circumvented 
by using agonists that activate vascular CB1-like receptors without 
activating CB1 receptors in the brain. There is evidence that activation 
of CB1-like receptors in hemorrhagic shock is not associated with 
marijuana-like effects, such as hypothermia and analgesia (Wagner et al.). 
Our recent findings indicate that the compound `abnormal cannabidiol` 
(Adams et al., Experientia 1977, 33:1204-1205, see also structure in FIG. 
8) may be a selective agonist of CB1-like receptors, and does not interact 
with CB1 receptors. In both anesthetized rats and mice, 10 mg/kg (i.v.) of 
abnormal cannabidiol (abnCBD) was found to cause hypotension that could be 
prevented by pretreatment of the animals with 3 mg/kg SR141716A (FIG. 9). 
AbnCBD elicited similar although shorter lasting hypotension, inhibited by 
SR141716A, in CB1 receptor knockout -/- mice (FIG. 10). Furthermore, in 
the perfused rat mesenteric vascular bed preparation (in which potent CB1 
agonists were found to be inactive), abnCBD caused vasodilation which 
could be inhibited by SR141716A (FIG. 11). These last two findings 
indicate that abnCBD induces hypotension via CB1-like (non-CB1) receptors. 
In other experiments it was found that abnCBD in doses up to 60 mg/kg does 
not cause marijuana-like neurobehavioral effects in mice (Table 1). 
Furthermore, using an in vitro ligand binding assay (Compton et al. , J. 
Pharmacol. Exp. Ther. 1993, 265:218-226), abnCBD at concentrations up to 
100 uM failed to displace .sup.3 H!CP-55,940 (a potent known ligand of 
CB1 receptors) from CB1 cannabinoid receptors in a rat brain plasma 
membrane preparation, a finding replicated 3 times. Saturation experiments 
of .sup.3 H!CP-55,940 binding (n=6) revealed a K.sub.d of 809.+-.21 pM, a 
B.sub.max (total number of ligand binding sites) of 1.2 pmol/mg protein, 
and a Hill coefficient of 0.94.+-.0.05, values similar to those obtained 
previously by Compton (et al., 1993). These latter findings indicate that 
abnCBD is not an agonist of CB1 receptors. 
TABLE 1 
______________________________________ 
In vivo effects of abn-CBD in the mouse model 
of cannabinoid activity 
locomotor core 
Dose activity antinocieption 
temperature 
immobility 
(mg/kg) 
(% inhibition) 
(% MPE) (.increment. .degree. C.) 
(%) 
______________________________________ 
0 0 .+-. 0 6 .+-. 3 0.5 .+-. 0.1 
0 .+-. 0 
10 0 .+-. 5 4 .+-. 2 0.3 .+-. 0.3 
0 .+-. 0 
30 0 .+-. 10 6 .+-. 6 0.4 .+-. 0.1 
0 .+-. 0 
60 6 .+-. 16 13 .+-. 3 -0.5 .+-. 0.9 
0 .+-. 0 
______________________________________ 
The above four parameters were measured as described in detail by Compton 
et al. (1996). Briefly, spontaneous locomotor activity is expressed as % 
inhibition vs. control. Mice were placed in individual activity cages 5 
minutes post treatment, and interruption of the photocell beams (16 
beams/chamber) were recorded for a 10 minute period usng a Digiscan Animal 
Activity Monitor (Omnitech). The degree of antinocieption (tail flick 
latency) is expressed as % of maximal possible effect (MPE). The heat lamp 
was maintained at an intensity sufficient to produce control latencies of 
2-3 seconds. Latency values for each animal were determined before 
treatment and 20 minutes following treatment with abnCBD. A 10-second 
maximum latency was imposed to prevent tissue damage. % MPE was calculated 
as: 
##EQU1## 
Core temperature was measured by a rectal thermistor inserted to 25 mm, 
before and 30 minutes after administration of abnCBD. Catalepsy (ring 
immobility procedure) was expressed as % of total time spent motionless. 
Mean values and their standard errors are shown. The number of animlas 
tested in each of the 4 paradigms was 6-12. None of the values is 
significantly different from the corresponding drug-free control value. 
Therefore, in a second preferred embodiment of this invention, the non-CB1 
receptor (cannabinoid receptor other than CB1) agonist abnCBD could be 
administered to patients suffering from diseases related to excessive 
vasocontriction. Administration could be by a variety of routes and the 
dose would depend on a number of factors, including the age, gender and 
previous medical history of the patient. In the clinical setting with 
human subjects, we suggest measuring the effects of SR141716A on pulse 
rate, blood pressure, portal venous flow, mesenteric arteriolar 
resistance, hepatic arterial flow, hepatic blood flow, and portal venous 
pressure. For example, patient response to the drug couldl be monitored by 
measurement of blood pressure at regular (eg. 10 minute) intervals. 
While the experiments above suggest the effects of the non-CB1 receptor 
agonist abnCBD, it will be clear to one of skill in the art that a wide 
variety of related compounds are available for testing or to serve as 
prototypes for derivatization in order to convert them to pharmaceutically 
useful non-CB1 cannabinoid receptor agonists. Examples of CB1 receptor 
agonists which can be used in the practice of this invention can be found 
in U.S. Pat. No. 5,532,237, U.S. Pat. No. 5,605,906, and U.S. Pat. No. 
5,631,297, all of which are herein incorporated by reference. 
While the invention has been described in terms of its preferred 
embodiments, those skilled in the art will recognize that the invention 
can be practiced with modification within the spirit and scope of the 
appended claims.